What kind of music do you want to play? If you want to play classic rock, classic country, classic blues, classic folk or new stuff but along those lines, that was/is pretty much all done on 4 stringers. Old school funk. Motown. Punk — 4 string. Grunge
If you’re into modern pop, modern country, [I guess, from reading on here] modern gospel, [I guess, from reading on here] modern Christian Contemporary (but maybe not the very latest stuff), fusion, [I guess, from reading on here] modern Broadway play-type music...well, then a 5 string is probably your best bet.
I guess Metal can either be a 5 string or a tuned down 4.
I’d say it depends on your vision for where you’re trying to go with your music. There’s a different visual impact between a 4 and a 5. When you look at basses in a store or online, which look appeals to you more? When you see someone playing on stage?
There is also comfort (weight, neck width) to consider. If you have small hands, consider a short scale 4.
Cost can be a factor (including the bass itself, but also more expensive string sets for 5ers and possibly the need for an amp that will do a low B justice).
There’s a facility, a practical benefit, to being able to get low roots and 5s without having to move to a new position on the neck with 5 strings, and lower notes for songs in keys like Eb, D and C (without re-tuning the bass or at least the E string) can sometimes be a real benefit. Tuning a 4 string BEAD could give the same benefit if such is desired, but then it’d be at the cost of a G string. Cello tuning (CGDA) can help a 4 string cover more range if needed (not common, but it’s possible). However, if the type of music you like was/is done on 4s, more range isn’t needed. It’d still be nice to be able to reach right up from wherever you are on the E string and grab a lower note sometimes...
Personally, for me it’s 4. I have no interest in any genre in which 5s are common; no players I like play 5s. The basses I desire, the classic Fenders, Rickenbackers, Gibsons, etc., are all 4s. If that sounds like you, get a 4. If you have different tastes and ideas, and/or need/want the facility of the extra string of a 5, get a 5. Regardless, good luck with your playing!