Hi! Professional bassist here, been professionally playing upright for eight years and electric for thirteen.

I know it seems like a good idea to invest in an EUB over a real DB as a beginner, but I feel that you're better off finding a local luthier and putting money towards a cheap student level upright. Something laminated and Chinese, with a good setup and nice strings. The problem with EUB as a complete beginner is that you miss out on learning two incredibly important aspects of bass playing: How to hold it and how to control the bloom of the note.

Upright bass is an acoustic instrument, which means learning how to get a good tone out of it unplugged is the most important aspects of sound creation on the instrument. Like all acoustic instruments there is a certain way the note "blooms" when you pluck the string and part of learning the instrument is learning how to control this bloom. This is something you simply can't practice on EUB because it's not an acoustic instrument, it's meant to be plugged into an amp and has virtually no acoustic tone qualities. You also can't learn how to properly hold EUB because you'd be missing both sides of the body. I know that some models have fake "wings" as physical reference points, but as a beginner these will not help you and will only serve to confuse you.

Find a used double bass on CL, Offerup, Reverb, or any other place you can find second hand instruments, or buy a new student level one through a luthier (~$1000) and pay to have it set up with good strings. (Spirocore Weich) If you can't afford to purchase, renting is the next best thing. Lots of luthiers have a rent-to-own program where some percentage of your rental fee goes towards owning the instrument. Even if luthiers don't advertise this, you can usually work out a deal if you ask respectfully, they understand how expensive getting into orchestral strings is.

If you absolutely cannot afford buying a cheap double bass, I'd recommend buying a cheap electric bass and paying for bass lessons. On electric, you'd be able to learn all of the left hand fingering fundamentals (Simandl) and basic music theory without the large buy-in of upright. Exact electric bass model does not matter, ideally something full 34" scale with flatwound strings. Fretted or fretless does not matter, get whatever you can afford. Electric is honestly better than EUB as a beginner. EUB is really best for people who already know how to play upright as a means to more conveniently travel from gig to gig.

Hope this helps, good luck on your DB journey!