I used to sell Victron and Mastervolt.
Both of these are great.
Had one customers Pro-Mariner hick-up years and years ago. I am sure but could not prove it's problems were customer induced. So, I really don't have a problem with these, but just never sold them.
These would be the three I would recommend.
You would be looking for a sized charger to well cover all the house loads while on the dock or gen-set.
Charger / Converter is a better descriptor here.
Your looking for a varied charge profile that finishes in a float level the battery type requires.
Chargers come with multi battery use (one charger, up to 4 batteries). I remember customers that wanted redundancy, 2 separate chargers (charger for each battery or bank).
Yea, Ex-Eastern pilots..
Your fixing to spend a few dollars. Don't cheap out on the cables to and from the charger either. If your old leads look skinny and tired, replace them with the charger project.
While your crawling around the batteries, check out the engines alternators, belts and V/A out -put.