not sure exactly what features you need but there are

• losslesscut
• avidemux
• mkvmerge and mkvmergegui

if command line is OK, ffmpeg is the most versatile and customizable and tons of support docs and question forums (superuser, stackoverflow, askubuntu) for every conceivable niche one-off operation

apparently Uk govt has never played watch dogs legion, nor seen Equilibrium (C Bale movie), nor Minority Report, nor Richard III, nor read Brave New World, nor the billion other movies, novels, games, poems, songs, Banksy art, social videos, cave paintings, etc that specifically warned UK not to (re)become the villain (over and over again)

it’s like the 2nd most popular culture topic… after “love” or something

but noooo, just had to be edgelordsandladies.gov.uk

…