I love my used HW90 .25. It is an "anti buying more self contained airguns agent", because every time I look at, become fascinated, by air rifles, I say to myself, heck the HW90 CAN DO THAT BETTER LOL.
Did you fix your barrel lock up? If not, you could get it out of the stock first. Then start by checking lock up wedge function. Then adjust barrel free drop as TBT demonstrates for weihrauch springers about 4:48 in at
https://airguncalculator.com/ I would not be grinding on OEM parts because many many units are in wild and factory parts has proven to be high quality.
Mine is a 2021 or 2020 product using Weihrauch's serial number driven online database
A user built database with Weihrauch products
www.weihrauch-database.eu
Beyond power adjustability, the trigger, the barrel, the longevity in Weihrauch's line and the many users who have posted online over the last 2 decades, rebuild-ability, ease of disassembly/reassembly, and parts availability, no flyers from my unit [running 19.xx and 20.09grains to start], I 'm sold on it.