Just wanted to clarify a few things. I have a class A CDL and have been backgrounded every which way under the sun with some of the jobs I've done. Maybe I can help a little with some addressing terms. I used to work closely with the USPS and it's 9,000 rules, acronyms and regulations. We had numerous customers confused between mailing addresses (as far as the USPS only is concerned) and street/physical addresses - which are not necessarily the same thing. This confusing difference is why a person out in the sticks can have a UPS shipment delivered to their physical house, but yet the mailman won't go there because the house has a PO Box actually as their mailing (USPS) address that UPS won't ship to. PO Boxes and PMBs are valid mailing addresses as far as the USPS is concerned, but they don't work well for some other things sometimes because it's known that those addresses are just facilities where mail is sent to on behalf of a customer. The trick is in differentiating the address types and terminology.
The SD residency affidavit is very simple, it's nothing anyone need lie on. It only asks if SD is your state of residence - which it will be if a DL, etc., was switched to there and it asks if SD is the state intended to return to after being absent. If one has their other services set up there, that need not be false. SD really doesn't ask much to be a resident.
https://dps.sd.gov/licensing/driver_licensing/documents/RESIDENCYAFFIDAVIT.pdf
https://dps.sd.gov/licensing/driver_licensing/obtain_a_license.aspx
I have a CDL/Real ID with SD - as a full-time traveler. Before I went full time, I moved states/addresses numerous times over so I've been to the DMV a lot.
Going as a full-time traveler in SD is not a big deal. As a traveler, in addition to standard Real ID document requirements, I provided a receipt from my mail-forwarding service and a receipt dated within the last year for a one night's campground stay. I even have a passport - sent to my forwarder. Because I have a CDL, the DL form asks for both a mailing/physical address. The physical address is the forwarder's physical street address. What appears on my license however is my mailing (PMB) address. I've had no problems in SD with that. They're used to it here.
I was grandfathered in with my insurance company, so I had no issues there. But - there are also places that cater to full-time RV insurance from what I understand if your insurance company does complain or refuse.
Banks. The bank didn't say a word when I changed my address with them, because all I changed was my
mailing address. They just require a physical address for CIP (customer identification program) when setting up new accounts for the most part, that address doesn't have to be residential - or the one they actually mail your items to. If your bank squawks about using your mailing address
for CIP purposes because it's a PO Box or forwarder, put down the address of a friend or relative, your storage unit, etc., whatever. If you don't have a permanent physical address, all you can do is get as close as you can. They just need something to satisfy that requirement. But you can keep your mailing address as it is;
mailing and physical addresses aren't necessarily the same thing.
If you have an established bank account already and then you go full-time, I don't think the address issue is so much a problem. When you contact the bank, you just let them know you have a different
mailing address. But for setting up new accounts, the banks don't like PO boxes & PMB addresses put in their CIP requirements because again, they want a physical address and those boxes are just places mail is sent/collected. Yes, it's a nuisance for those who travel full-time. But that's why you put down the physical address of a friend, relative, etc., etc., it's just for CIP. You can still keep your mailing address otherwise.
I think being fearful about being monitored or stopped from living how you like, or what-have-you, has about as much energy as one gives it. That's not a dig at anyone - what I mean is - it's your energy, so take it back and don't feed fear or discouragement, and you can find solutions. Morally speaking, carry with you the knowledge that you're not doing anything wrong or hurting anyone else by traveling, so don't allow yourself to be made to feel you are. Approach things from that mindset and don't dwell too much on semantics. Carry on and find the ways you CAN do what you want.