Before buying a "glamping battery", you'll want to ensure that it can be run unattended in your desired configuration.

I previously had a Bluetti EB70S and while it almost did what I wanted, it could only charge from AC or Solar, but not both and didn't have a way to set desired levels.

Now I have a Bluetti Apex 300, and I can set it to charge to X% off AC during overnight off-peak rates, and never drop below Y%.