Is it worth it to start a YouTube channel these days, or is it too over-saturated?

If the topic(s) interest you, and you think you could do it with consistency and some level of good presentation, then yes. If you are hoping to make money, then no.

It very much depends on your what you are hoping to get out of it. I've been running my channel for years, nearly 60k subscribers and it makes around $150 a month, and that's with a lot of work, a lot of videos and it in no way covers the cost of making them. However, YouTube is still a massive resource and is often the first place people go looking for entertainment or instruction. So, if you have something to share that's of interest to people then YouTube is a great platform for it. So, if "worth it" means helping people then yes, do it, but if it's about money and fame then those things are extremely unlikely.