Get an D-RGB Hub like this
https://www.amazon.com/RGEEK-Splitt...hild=1&keywords=RGB+Hub&qid=1605926771&sr=8-4
This is a completely passive device that merely connects all ten of its headers in parallel. Thus, it gets all power for the lights from the mobo header, and for most fans you can connect six fans' lights to a single header OK. The Hub comes with a single input cable that takes up one Hub port and connects to the mobo D-RGB header, leaving you with 9 outputs to use. Do NOT try to use the mobo plain RGB header.
The fans with the case have non-standard connectors on them. Your easiest path for those three is to connect them to the case's D-RGB control board as designed, and then connect a cable from that to the "mobo D-RGB header". Except, you will connect that to one of the Hub's outputs. The case's controls for lights includes a way to let the mobo signal take over, rather than using the manual buttons of the case controls.