Should I do this unit wasting my 9slot

yes as there are lots of awesome combo problems by type. You will see that the Evan-combo way(rigid free etc) actually can be applied into the problems in the wild. Yet there are problems which is necessary combine these tools to solve the mixture. Not intimidating as the legends call it so have a try if you have some prior experience in general combo

Notable problems

china TST 2017/3/6

USA TST 2018/6

Tournament of the towns

BAMO 2020

What’s surprising is that contrary to the common beliefs, the ToT problem and the BAMO one is actually harder than the infamous TST. You will see that for some problems, it is better to think it in a less fancy way such as toddler yourself doodling with color blocks. And these problems with a hint of ingenuity is in fact, MOHS 60.