>>39638274From my own impressions:
If you're a male and care about numbers, Niji is the better choice.
If you're a female and care about numbers, Holo is the better choice.
If you have distinguishable, but also broadly marketable talents and wish to get support that is catering towards it, Holo seems like the better pick between the two since they seem to allow and wish for a tiny tad more individuality compared to Niji despite being also more restrictive with content and permissions. Also keep in mind that HoloPro doesn't release new waves very often, which means competition for the few spots will be fierce. Also keep in mind that you should be open towards idol typical activities such as singing, releasing song covers or originals and eventually for some basic dancing too.
If you feel like you don't have any outstanding skills, but still think you can make it as a general streamer, Niji seems to offer the better chances, but with the trade-off that they likely pick their talents to match the market's most popular taste (humor, personal taste in gaming and music, hobbies). More recently Anycolor has seemingly also become more encouraging regarding idol activities, so even if they do not explicitly state that you need to engage in any related activities, you should keep it in the back of your head that you will eventually see involvement of some form. So being open towards these things is a plus too. On the other hand despite the frequent releases of new talents, not many of them stick out giving off the impression that individuality and eccentrism for recognizability is not as much of an important factor for them compared to easy marketability, which in the end means, if your tastes and ideas are too specific and niche, you may be not what they are looking for.
Either way I would recommend just starting out as an indie and try out being a vtuber first. If you have very concrete ideas about what you want to create and become, want to keep as much agency about your content as possible and feel like you don't fit into the image of above mentioned, I would recommend staying an indie and working towards creating a niche for yourself.
And last, independently from whichever you chose, keep in mind that versatility is always appreciated and helps you become a more well-rounded talent.