I play a lot of super low tuned stuff, I'm also a bas player and I've had a lot of experimentation. I once had a 135 bass pack on a standard American strat guitar. Sounded terrible BTW. however there are ways around low tuning problems.
I currently have the strat in F#, so nearly a full octave down, and a baritone in drop E. the baritone sounds amazing, now I did some tweaking to the strat to accomplish this. Off the shelf it sounded awful anything below drop C-B range. I filed the nut out, drilled 2 of the tuners wider and got a pickup modeled after the Seymour Duncan Nazgul series.
I got an 85-18 set of strings from Stringjoy.com and it sounds great. You really need the massive strings but even an 85 in E would work and a 50 dollar pickup designed for heavier tones. It's still a 26 inch scale and the necks holds up fine.
The real problem is your bass player. If you has a bassist or want one in the band at all, low E0 is hard. You're talking about absolute necessities for the bass being at least a 36 inch scale probably expensive bass, definitely some active pickups, strings in gauges that is difficult to find and will cost a fortune. So getting a guitar down an octave isn't that bad, the bass getting an octave lower is nearly impossible without a whole rig and instrument upgrade and a lot of money.
Being a bassist myself, if a band wanted me to play with them and they said they tune down an octave I would just walk away. I never tune below A0 for a bass because of the problems, so if you wanna play heavy stuff and not screw the bassist over, id say the lowest you should go is G# or A, depending on the rig. Most 5 string-basses can handle low A, and G# is even possible with the right amp and some Stringjoy 145 guage strings.
Drop A still sounds fine with chords too so it’s a good happy medium of not needing heavily modded instruments and not losing chord capabilities. I only have guitars tuned in F# and drop E because I used them for solo projects where I essentially AM the bass player. Animals as leaders does that. its not great for super heavy stuff because without the bassist everything feels flat and hollow, but for some music its fine, more ambient and tapping works without a bassist.
Now if you absolutely need that low E tuning, and modding isnt an options, lets assume there is already a band with a bassist an octave down and E is what you MUST have, you totally can just use a bass and run it through a guitar amp. crank the highs and roll the bass knob down to nothing, keep distortion moderate and run the bridge pickup, play with a pick and you essentially got an 8-string alternative on a budget right off the shelf. You can even buy like E-a-d-g-c extra lights and put them on a 5-string bass and they will have that looser oscillation sound that works well for Djent or metal. a 90 guage string on a bass will sound as good as a 90 on a guitar and it will have more clarity from the longer scale.
lastly, if you get a line 6 Shuriken guitar, you can buy regular strings and it digitally tuned down a full octave without losing tone quality. 12 ft ninja uses that and they play an octave below drop D in some newer songs and that’s with a set of like 48's physically tuned to regular drop D. and that beast sounds amazing. its also like well over a grand just for the guitar alone, and 500 for a pedal. so ideal, but not cheap.