I am responding to some older battery replacement questions because now is the time some of the older Varta AGM batteries will need replacing.
It is a nothing job. Don't fret and try to read too much into it.
First, I am an electrical engineer. The techs at your dealer aren't. They just learn by rote and spout nonsense they have read.
The fact is your dealer hasn't sold enough eGolfs to be proficient at repairing them. They just rely on tech notes from VW and the tech notes are often just cut and pasted from previous nonelectric modes.
If you haven't figured it out by now, dealerships make most of their money on servicing.
They often use the shotgun approach and just replace parts until something is fixed.
Even if they know exactly what is wrong they will often still sell you parts or services you don't need.
Volkwagon eGolfs use 12 volt AGM only. no other type. Ice cars often use different battery types and have microprocessors that monitor the charging current and voltage.
If you replace your battery with one of the same type and current rating no adjustments will be needed.
If you replace your eGolf Varta AGM battery with an AGM replacement, no coding will be needed PERIOD.
I just recently replaced my 6+ yr old Varta AGM with a Walmart:
EverStart Platinum AGM Automotive Battery, Group Size H6 12V, 760 CCA, $169 + tax
It is exactly the same size and form factor of the VARTA. They are amazingly the same and fit exactly. The EverStart battery has a 4yr full replacement and an additional 3 yrs pro-rated guarantee.
This is the first battery I have ever bought (though I haven't had to buy many) that had a 4-year full replacement guarantee. My previous batteries have always had 4 to 7 years pro-rated.
The Everstart has a slightly higher capacity rating of 70 amps vs 68 amps for the Varta.
This capacity is within ~3% of the Varta. I expect zero charging problems.
I used a lithium Ion 12vdc jumper (pocket size) from Amazon to keep 12 volts applied while I changed the battery.
You probably wouldn't need to do this, but it keeps you from having to reset the clock time, etc.
So far, zero problems, and it fixed the 12-volt battery needs charging warning.
If my battery fails in less than 4 years, I will eat crow and notify the forum.