In my 2021 user manual under Winterization, it shows two methods after the part about draining the water system.
Step 12 "At this point, you can continue the winterizing process by either adding plumbing anti-freeze to the system, or blowing out the airlines. See below for the process on each."
You only do one or the other method. They both are acceptable, but if you use the pink RV antifreeze, you need to carefully flush the water system with fresh street water, and repeatedly fill and flush the fresh water tank to get rid of any residual antifreeze. It is not poison but you shouldn't drink or cook with it unless you have thoroughly flush the tank and all the water lines.
I have a Truma water heater and you are correct that you need to bypass it when winterizing since the antifreeze can corrode the heater. BTW, there is no hot water tank with the Truma.
I don't see it in my manual, but it is a good idea when de-winterizing to ingest a small amount of diluted bleach into the tank, then proceed with the normal fill/flush. This both sanitizes the fresh water tank & lines, and kill any algae in the system. Again you want to repeatedly fill and flush the tank/lines since you don't want to be drinking it.