You can install it via Powersaves,
however the Powersaves version has not been released yet. It will work, it can fail to launch Homebrew occasionally, but it will work.
Actually, the Powersaves version (including v11.1.0-34) has been
released!
Ah thank you very much KunoichiZ! Great to hear confirmation from someone who has experienced success with it. Also, after doing this myself, I can confirm it does indeed not only work but that all you need to do is:
1) make a back up of your save file, doesn't matter if you want it or not- you just need a save file made.
2) download the appropriate powersaves .bin file for your region. if you get a "corrupt save data message" then you selected the wrong cardid folder, use the other one. the file you need to use inside of that is the one that corresponds to your region, and then the one that matches the name of your ropbin file that you would download from the homebrew website. you simply input your firmware version in the numerical fields and then click download to pop up the download message which identifies the appropriate .bin file to use.
3) copy and paste that file into your powersaves folder (Users/YOURNAME/powersaves)
4) rename your original back up to something else so that you can try again in case you messed up.
5) rename that .bin file you got from the powersaves folder from the oot3dhax download to match the name of your original save file (copy and paste the info before .bin extension)
6) go to restore the save file using powersaves and a new local save should be listed and will be named something like oot3dhax (idr I didn't pay THAT much attention) and that is what you will "restore".
7) boot up your game, if you did everything correctly you will be able to select a save file and the hax/HBL save slot will have some ridiculous name that extends past its limit, if you got the save data corrupt message then you simply used the wrong cardid so try the other folder.
I hope this helps clear up all the confusion for everyone, hopefully I helped the veterans here. I am new. Thanks to KunoichiZ, the member who posted the youtube video, and that youtube user himself.