DIY main battery swap on Volvo V70?

The car is a Volvo V70 2.0 D4 181 Momentum from 2014.

I bought it used in 2016, but in 2017 it started having problems with the automatic start-stop thing, and a year later it started saying "battery low" when parking. I have had it checked out by a garage, and they say that the generator and battery are in good condition.

Since then, the problems have been stable, but persistent. It has not had start-stop for a long time now. I recently read that start-stop requires a certain type of battery, and I do not know if that is what I have installed.

I’m thinking I should maybe buy a brand-new "proper" battery … but I am unsure of the consequences of simply unplugging the battery in a modern car.

Do I need to have a garage do it? Can I do it myself, and if so, is there a certain protocol I should be following (beyond terminal dis/connect order), I mean to ensure the electronics and locks and such don’t go wonky on me?