I would probably reseal the whole tank.
But I’m overly cautious when it comes to things like this.
I’ve had a few leaks over the years and seen first hand the damage that can be caused.
You could add some bracing down the sides.
It’s not as aesthetically pleasing but it will add another layer of sealing and strength.
I’ve done this for a friend that happens to own a LFS.
He had a 125 that was used for quarantine in a back room. He didn’t care about looks he just wanted it to not leak.
Its still running without any problems.
All that being said.
Their are a few factors to consider in this particular situation.
Is the tank in a place that if it leaked or failed it wouldn’t cause much damage?
Having filled the tank and watching it for a while, does it seem stable or is it continuing to get worse?
If you answered yes then I would just bite the bullet and get it over with.