Earlier quoted context omitted.
There definitely exist full-featured models that replace only the seat of the toilet—a 5-minute, highly reversible effort well within the capabilities of even the most nervous renter. The water hose stacks inline with your existing supply at the point where it enters the toilet basin—a simple unscrew-and-rescrew operation on the order of attaching a garden hose. If the seat and water are heated (vigorously recommend!…
Power outlets are not allowed near water basins here and so are not installed into the wall near the toilet. Most often there’s only one outlet near the sink with a circuit breaker on an opposite wall. Heated is not necessary in California and more complexity means more likely to break, so YMMV.
I've definitely seen homes here with outlets near the toilet as well, with no extra safety devices beyond GFCI.
(And a quick search suggests that building code requires an outlet within 3 feet of every wash basin.)
If you are not talking about California, then... bummer; that level of restriction seems entirely unnecessary for safety.