Don’t know what you’ve seen or where you’ve seen it but … If you like what you have seen so far, keep watching in chronological order, based on release date
Kumiko timeline:
First Year Student TV Anime Season 1 + “Yōkoso film” 響け！ ユーフォニアム 北宇治高校吹奏楽部へようこそ
Japanese with English subtitles: Sound! Euphonium: The Movie - Welcome to the Kitauji High School Concert Band
First Year Student TV Anime Season 2 + “Todoketai Melody film” 届けたいメロディ
Japanese with English subtitles: Sound! Euphonium: The Movie - May the Melody Reach You
Second Year Student Liz to Aoi Tori and Chikai no Finale
Liz and the Blue Bird
Sound! Euphonium: The Movie - Our Promise: A Brand New Day
Third Year Student: TBD
If you don’t like what you’ve seen, you still may want to give Liz and the Blue Bird a try.
If you haven’t watched anything yet, and particularly should the opportunity present itself to catch a theatrical screening, you could start with Liz, since that cinematic experience can stand on its own. Then watch it again whenever the mood strikes … or never again
Given the topic title and the fairly recent news about availability on that platform, I’ve mixed in a few Tubi TV links. Regional. Mileage may vary.