I have a very hilly front yard (estimate 50 degree slope). Over the course of 12 years or so I wore out two high quality 4 cycle lawn mowers (Snapper) due to continual oil starvation from the slope mowing. I then made the switch to a Lawnboy with the Duraforce 2 cycle engine. I fell in love with the power and light weight of that mower. Unfortunately it has become difficult to start when it gets hot so, last year I bought one of these
https://www.lowes.com/pd/Kobalt-80-...21-in-Cordless-Electric-Lawn-Mower/5000859515.
It has been great! It uses the Briggs power plant and battery system. It is about the same weight as the Lawnboy and I love the idea of not having to deal with oil, premix, gas, and all of the other stuff that comes with small engine maintenance. After I got it, my neighbor asked me if I would be buying a Tesla or Chevy Bolt, and I answered "heck no". I also have a Lynx cordless blower and string trimmer from HF, but I am not sure I will ever make the leap to an EV. So far I have not missed the small internal combustion engines for lawn appliances. I have rather large corner lot, and the only adjustment that I have made since the mower purchase is to buy a smaller spare battery in the case the grass is really heavy and I need it to get through the last part of the yard.
Good Luck on your continued search and I hope you are happy with whatever investment you make.