LaymooDR wrote:

1. There are barely anyone who actually goes through and replies to requests and the post just sits there and expires. I had my collab request ignored for almost a week, so I got it deleted.

It might just be my opinion, but 1 week is not enough time.
People don't check the forum or mapping discord servers daily, often it is on a 3-4 day basis or in case of some mappers I've talked to in the past, week by week.
The first time I tried to make a collab it has been sitting unanswered for a whole 28 days, and it then took another 4 months to be finished.
What I'm saying is, it will take time to get people to look at your post, and even more time for parts to roll in.
Getting people's attention can depend on song choice and the general appeal of your already mapped part/your other maps, which I'll go into more detail about further down.

LaymooDR wrote:

2. It's impossible to find the right people to work with. There are only a handful of well-known users who are good at mapping (Sytho, Mismagius, Sotarks, etc). The problem being that there are a ton of users who are not really good of creating maps and it makes it hard to find an obscure underdog of mapping who would like to contribute.

There sure are many mappers who are good at making maps, sure they might not be as well-known as the big names you mentioned. I only heard of Sytho today >.<
Sure there are also many mappers who might not be good at making maps but that's just how it is, getting good at making maps takes practice, which is gained over time.

Also, what you said could also be applied to you, the part about not being really good at making maps.
I've looked at all 4 of your submitted maps. 2 of them are not finished/mapped at all (I'm aware you purged one of them), the others are rather Hard difficulties and (in my opinion) not really good either.
Those maps coupled with the fact that you have literally 0 playtime in the respective mode would very likely turn away potential collaborators, they could argue that you're too inexperienced to even try such a project and that it wouldn't be worth the time spend on a map that would just sit there collecting virtual dust.

Just get more experience, try to make actual beatmap sets with more than just one expert difficulty, and show that you know your way around the editor and your chances will increase the more you strain away from the "total newbie" look.
I just now noticed that you've been part of this community for not even a month, this is likely the biggest red flag with the low amount of actual maps you've made/submitted.

LaymooDR wrote:

3. Sometimes, the collab just wastes everyone's time if it is too long of a chosen song. I was going to get Egoless mapped, but that ended up being too long to even start it, so I had it shelved and decided to delete it as soon as it get graved.

Song choice can be a major factor, which I guess you're aware of.
In the case of Egoless, I can see the problem of it being too long (60 minutes )
Long songs/albums like such can be mapped, but it takes time and effort, and, as Ryu mentioned above, it takes motivation.
If you were to attempt a song like this, maybe cut it into parts, like Because Maybe, which has a playtime of 57 minutes total.
For the start I really do suggest something shorter, not a tv size of course but something in the range of 3-8 minutes if you really want it to be a collab.