It's funny how polarizing these threads can get!
I can't recommend a unit based on direct experience, however, I'm at a similar stage to the OP and need to replace my aging 15 year old Garmin unit. I have a broadly similar set of needs to the OP as well and will be using it for long complicated off-road tours with little need for training metrics.
Unlike the others above, I have settled on the Garmin Edge Explore 2 as meeting my needs perfectly and will be purchasing one later this year as and when funds allow.
A lot of the advantages that people outline for Wahoo units, are for me, negatives.
Setting up your device via an app on your phone? no thanks, I'd rather not need to rely on yet another piece of tech to operate, I'd rather sit down with a cup of coffee one evening and set up my Garmin on the unit.
Flashing lights to tell you where to go? again, no thanks. I like to leave my head unit on the data screen, with a couple of metrics like time and current speed displaying. Not only does this make the battery last a lot longer, but it's then not distracting me. I can then lose myself in the ride, look around enjoy the scenery, hum silly songs to myself, whatever. If I need to turn, then the unit will beep at me to wake me up and show me the way I need to go. I'm sorry, but I could easily imagine me missing flashing lights a lot of the time.
Buttons? again no touchscreen is a deal breaker for me. I need the ability to easily and efficiently look at the map screen from time to time and scroll around it effortlessly. My current head unit uses buttons to scroll around the map and I hate it, it's really clunky and hard to use. I get it when people say that touchscreens are hard to use at 25mph, but I have no desire to use it at 25 mph, I stop take a drink admire the scenery and then use the head unit.
Both Wahoo and Garmin make great head units and it really comes down to the nitty gritty details like above. I know what works for me and what doesn't, so for that reason I have made the choice I have made. There is no right or wrong answer, you just need to look at the detail of the different units and make a decision based on what you need and can live with.
As usual the excellent DC rainmaker review of the explore 2 is here:
https://www.dcrainmaker.com/2022/07/garmin-edge-explore-2-in-depth-review.html