GoldFinger
If you feel like you're rushing it then finish Magicians first. Do what feels right to you as the author. IMO, from my perspective, it didn't really feel rushed to me nor did I feel like there was a lot left undone - because I don't know anything about Magicians. I've only seen a trailer to the show, but never watched it or knew anything about it until now. So while I wouldn't mind if it hurried along, my position of it is bias. It seems to me that the MC was already powerful enough to not necessarily need to struggle much, and had metaknowledge and knew precisely what he wanted to achieve. As such it didn't feel rushed to me that he was able to do it all. Though he still needs to find Wanda and she might appreciate staying for a while to learn their unique magic.
In regards to Dragon Ball, will he be arriving in actual Dragon Ball era - like Kid Goku era? Most of the bigger threats are a non-issue then and he can have a good decade of relatively peaceful research. Seriously though the powerscaling of this series is insane and all over the place with a lot of power-ups that while mean little in the show would be considered practically god-like in any other setting.
Try to never force something while writing. It just leads to a loss of will to keep going. Just go for whatever feels right. Also some of the arcs don't need to take nearly as long as the original. The deal with the fairies would take like half a chapter since he'd just give them their own subspace and the slave ones in exchange for the key. Heck now that he has quasi-divine powers he could make a pocket space for them that can support their life without tripping the firewalls and he can easily just remove the necklaces by removing their heads and then reattaching them with some sort of healing. So the main points would just be wanda, god stuff and dealing with the true wellspring. Most of the later seasons are dealing with magic being turned off, the dark king and the library. Magic being turned off can be dealt with pretty easily. With the binder he could learn the spell to break the god apart like his sister. He could even give Eliot and Margo semi-divinity as thanks with his organs. The dark king was only a problem because of martin chatwin speaking from the other side and telling his brother he was his dead lover and how to come to get him by releasing the grabbers. So that whole arc never happens now because mc used his soul to power his anti-divinity blade. The library was only a threat because of their access to the wellspring which without the group getting past the puzzle and the filter on the magic in the source means they are not a problem and are instead just a collection of decent magicians the mc can overpower. The couple have the yggdrasil seed would trade it for a child which the mc could easily handle.