I'm fortunate enough to be a homeowner, but I rented places for most of my adult live. My current home doesn't have central AC, and none of my rentals did either.

Everywhere I've lived, the mounting hardware that comes with portable ACs just didn't work for me. What I found that did work is to throw away the existing window mount and build your own. I'll take two pieces of plywood, cut them to the space that exists in my window (at one point this was a sliding door), and sandwich a sheet of insulation foam in the middle. Then drill holes for your AC tubes and screw on the mounts that came with your AC.

Also, if at all possible, avoid the single-hose portable units. You're wasting cold air. A dual-hose unit uses outdoor air to cool the unit itself, and the hot exhaust gets expelled through the second tube. Do make sure you have a screen on the inlet, though, unless you want to be cleaning out bugs from inside your AC. I have used window units, single-hose portable, and dual-hose portable units. At least in my experience, the window units work best, the dual-hose units are a close second, and the single-hose units are crap.

As far as HA integration, I recently went through the process of finding a new AC that works with HA. What I found is that everything available either requires internet access and works with proprietary "cloud" access or just doesn't have any sort of remote connection. Some of the "cloud" solutions have decent integration with HA, but I have a hard-and-fast rule that none of my IoT devices access anything outside my home network. What worked for me is buying a "dumb" portable AC with a remote control and using a Wifi-connected universal remote to provide access to HA.