You can get cold water only ones but it's easy to find hot and cold water bidets that don't need electricity. Who can argue with 2000+ butts?

I installed a seat replacement bidet in my old apartment and didn't have any issue removing it and replacing it with the original when I left. My first installation took about as much effort as assembling Ikea furniture (which is simpler than assembling anything non-trivial by anyone else).

I recommend warm water bidets, but there are two routes that you can take: electric heaters or getting warm water from the sink. Electric heaters are more expensive but also easier to install if you have an open outlet. My recommendation depends on your budget. I'd say go with the best of these that you can afford. Then, if you want to do more research, take the option I recommended and see what other options are at that price point, look at comparison videos on Youtube and articles (Many Bidets has several and there are blog posts about many, too), and figure out which features you think matter the most to you.

1. The LUXE Bidet Neo 320 is $52 on Amazon right now. It goes under your seat rather than replacing it. This uses your sink's hot water connection.
2. The Brondell Swash Ecoseat S102 is $120 on Amazon, though the round seat option is sold out. This is a seat replacement option. The controls are worse than the Neo 320 and the hot water connection tube is shorter, but the spray is better and the lid is sittable and slow-closing.
3. The Brondell Swash CL1500 is at Costco and sometimes drops as low as $150, but is showing at $220 for me right now. It has a soft close lid (not sittable) and a heated seat with a hybrid electric water heater offering "continuous hot water," oscillation, warm air dryer, adjustable front/back position, temp, and pressure, a deodorizer, night light, etc.. I have not used it but I believe the main downside is that the water pressure is not as good as more expensive electric options (and most electric options are going to have less water pressure than non-electric options).
4. There are many options starting in the $300+ price range, like the Toto C100 and Swash SE400.
5. The Bio Bidet BB-2000 - currently $525, but you can email them to possibly get a lower price. I think I got mine for about $475 but there were a couple sales going on at the time. This was my first bidet and it's the best one I've tried so far. In addition to the features the CL1500 has, it has a remote + controls to the side, a vortex spray, a good amount of pressure (also adjustable), and actually continuous hot water. The only thing I would change about this is to give it a sittable lid and adjustable spray width. Bio Bidet has other options that also have decent reviews.

There are options beyond that range but I can't recommend them as I haven't tried them myself. If your budget supports buying an $800 bidet seat, check out the Cascade 3000 and let us know what you think of it.

Oh dont worry once you get bidet you wont have any regrets.

These are good, solve hot water problem and dont cost $500. Theres one of these at my parents house its fantastic. To avoid being sprayed with cold water you can turn the nozzle clean and other dial to hot, warm up the water stream for however long, then hit it cold for a second them go to wash. Seems complicated but its not. Gotta be careful not so scold yourself but its easy enough to avoid.

https://www.amazon.com/dp/B00JG3NVG2/ref=cm_sw_r_apa_i_mP1PEb2K9ZYBA

https://www.amazon.com/dp/B0713QKDYC/ref=cm_sw_r_apa_i_oN1PEbXJHGFGN

These have a lot of oomph than my fancy electric one.

Don't even have to do electricity to get hot water. Installed two $55 hot water ones last week in our new house. Just ts into both cold and your bathroom sinks hot water.

How does the non electrical bidet heat water?

I'm looking at this one and I'm not sure if it needs a hot water source or if it's magic.