One of the first projects I did was an IR setup for my AC window unit! At the time there weren’t an overwhelming number of options, but I settled on a Broadlink IR remote like this one: https://www.amazon.com/Broadlink-RM4-Universal-Control-Compatible/dp/B07ZSF46BX

I don’t have it running anymore, but I remember I was able to train it on codes through HA. The training process is subject to a little randomness in the IR signal from your remote. To get the codes right I wound up sending the training signal several times (I’m a nerd so I definitely did at least 10), then copying them into excel to find the statistical most common hex pairs to make up the code I saved in HA, e g.,

FC:G3:D4

CC:G3:B4

CC:G5:D4

Becomes CC:G3:D4, and that dramatically improved the success rate of using the trained command to control things.

For the garage opener, honestly the wiring on those are pretty simple, easiest option is definitely to get a specialty made controller like https://www.amazon.com/Smart-Garage-Opener-Chamberlain-myQ-G0401/dp/B08GD3D9YJ, but a simple Shelly relay can do the job in most cases.

If you’re really wiring averse, you could try something like this: https://www.amazon.com/Automation-Ceiling-Fireplace-through-Control/dp/B071GVGVVH

It says its not for garage doors so be prepared to have to return it.

If youre feeling really clever, you could also consider something like a Switchbot with a dumb remote, and just keep the remote in your garage. https://www.amazon.com/SwitchBot-Smart-Switch-Button-Pusher/dp/B07B4D9KVX