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Yes, of course you can. Please read all of these instructions before following them.

Backup archives are stored in your backup output directory. If you have not changed it, it's administrator/components/com_akeeba/backup.

First of all, make sure that you download these files and keep at least one more copy of them on an external drive or something similar. If you lose your backups you're toast, basically.

Then, you need to copy the backup archive of the latest backup to your site's web root.

Delete all other Joomla folders from that folder: administrator, bin, cache, cli, components, images, includes, language, layouts, libraries, media, modules, plugins, templates, tmp.

IMPORTANT: You MUST delete these folders, otherwise the downgrade from Joomla 4 to 3 will NOT work. By removing these folders you are also removing your backups, which is why I told you to download them and keep an extra copy of them before you do anything else.

Download Akeeba Kickstart Core from our site. Extract the ZIP file on your computer.

Upload the extracted kickstart.php to your site.

Then the process is exactly as shown in Restoring a Site on Any Server.

I have done that myself. My first upgrade to Joomla 4 (back then: Joomla 4.0 Beta 1) was not exactly what we'd call a success. Actually, I screwed up my test site pretty badly :) It took me two tries to figure out what I was doing wrong (a system plugin was killing the last step of the upgrade, I had to disable it before upgrading the site) and between these attempts I followed the exact same process I have you above. So, don't worry, crap happens and yes, the process I gave you is tested. I would never have you do something I wouldn't do myself!