OTOH, in OP's case (independent if it's testing in VM or wherever else), i'd use fpcupdeluxe, select the "generic" branch (stable, fixes or main), and fire!
that way i can stay current with updates without having to juggle different Lazarus-versions each with its own config
Ah, well, as an old System Admin and therefore, by definition a Control Freak, I want to see whats happening. So, my general recommendation is always build Lazarus from Source. But OP asked about Debs.
fpcupdeluxe is good, I have used it for a microcontroller project where I could not be bothered working it all out myself. But for normal Lazarus installs source build is so easy and I can see where everything is.
Davo