I consider off line maps a must for when travelling, so when you don't have wifi or mobile data (I was making the assumption I'd not have either during the day to cover all bases) you can still find your way around.
Previously when I travelled I used City Maps 2Go Pro for my offline city maps, I've not used it in recent times as it hasn't been maintained so swopped to using maps.me on my iPhone for offline maps locally. From my planning, I got hold of/generated my cycle routes as GPX files and loaded them into maps.me (as bookmarks), well kinda ... I had to convert them to KML before I could do that if I recall. The app wasn't that great at handling that so I tried another app (which is based on maps.me)
I settled on using Organic Maps, this is essentially the same as maps.me functionality wise but it handed the bookmarks way better (and from their info "free privacy-focused fork of MapsMe"). I downloaded all the routes and maps for everywhere I'd be so I'd have them offline to save on data, or if there wasn't data. I wasn't planning to do the whole GPS style directions but more to see if I was on the "blue line" still when I was going along to know I was on the right track.
Onto using mobile data. Most of this year I've been using an eSIM offering from a service called DENT Wireless. I use this even in South Africa for my mobile data, even though my voice plan is with Vodacom. Why? Well ... it's fantastic that's why, and I'm getting my data for free. DENT has a crypto currency as well which you buy then use that to buy data, but you can quite safely ignore that totally.
Basically if you have a device that can support an eSIM you can just install the profile/eSIM and you are ready to go. The data you have can be used worldwide, well ... not everywhere but in 70 countries. Obviously South Africa is one of those. When I started using the service I got 200MB free to try out, and saw it worked really well. Then ... how to get more? You can buy ... or you can be clever like me.
Each day there are 2 things you can do in the app. Basically watch ads (which I don't actually watch).
First is to do the 5 daily (it's based on a calendar day) "top of screen things" where you earn
So basically every 5 days you can score 100MB of data. Each data bundle you get (in this way, or buy from them [there is a market place but thats another story]) lasts for 365 days.

Day1

After Day 5

Earn screen showing spin wheel

Spin wheel showing what you can win
Actually probably easier to show a video that I found I had made (I edited the middle bit so you didn't have to wait through the whole ad)
Under normal data usage circumstances in SA I use minimal (as have wifi at home and work) mobile data, so that is ample for me to have "free mobile data".
Secondly there is a spin wheel thing, you spin and see what you get. Quite a few times I've landed on the 1GB data - whoohooo. You then have to wait 24hrs to spin again, that isn't calendar day but 24hrs since you did it last. So I have a daily routine, I have an alarm that goes off at say 9:32am, I then spin, see what I get and set the alarm for 9:34am (only do the alarm a bit later as I dont want to be notified right away as the time isn't at that yet) the next day, so I don't forget to do it. There were times when I forgot to do it and got annoyed at loosing out/not doing the spins optimally.
So how good is it to do this ... is it worth the hassle? ... well ... at time of writing this I have 24.06GB of data to use and NOT paid a cent for it. I have quite a bit of DENT now so I could buy data if I needed to. So most definitely, YES, in my opinion it is well worth it.
If you want to know more about DENT (I'm not affiliated with them in anyway, I just like the offering, chat to me. Here is a referral link that you can use to get started with 1GB free (and I also get 1GB free if you do)
Back to the holiday ... DENT's eSIM mobile data works in Germany, Austria and Turkey - all the places I needed it to work so - fantastic.
I have had a SIM before in Germany but wasn't ideal and didn't have masses of data, admittedly times have changed since then. I will say having mobile data for other maps (eg Google Maps), searching, keeping in contact with friends and family was amazing. It is a game changer vs being disconnected. Yes, maybe being disconnected is good, but I felt it was way better to have comms for various uses, I'd have been stuck a bit in Istanbul on way back had I not, you'll read why later.
Mobile data was fast and I could do video calls to people and worked flawlessly. I even used it at the one hotel vs their wifi as that was spotty so just turned that off and used my mobile data instead to upload things etc. When I started the trip I had 15.42GB and I think when I finished my travels I had almost 2GB more than that and I had used it loads. The data exits the mobile network in either USA or Israel depending on the APN you put in.
Update1: Last week I got an email from DENT: "In order to respond to the growth we see on the platform, we have made the decision that all DENT Bonus Data will now have a validity of 7 days. All DENT Bonus Data received in the past year will have a validity period of 7 days on 28.11.2022 . Please remember to use up any of your bonus data prior to 05.12.2022. Any purchased DENT eSIM Data will continue to include 365 days of validity following purchase"
Update2: They no longer have the spin wheel for daily bonuses and the daily thing is just for data not for DENT anymore.