Update: both Fossify Gallery and Fossify File Manager can do this! Just found out :) you select the first image(long press) then long press the last image of the group, it selects them all

Mm basically Ctrl + Shift + select but on a phone.

Not a real solution but a couple of workarounds with Material Files:

• if part of the filename matches (like photos taken during 2026-02) you can search then "Select all";

• turning on its FTP server than managing from a pc

Real solution would be a file manager with advanced search, that can filter by date range for example.

Mixplorer cam do this. It isn't available on F-droid and costs money on the Play Store but is free on XDA.