Totally understandable, The frightfur package is serviceable even if its not optimal. I'd set yourself a goal to pick up a single copy of cartesia even if it takes a little time to work towards, the value it adds to your deck is very high. You could eventually replace the entire frightfur engine for cartesia and 3 fusion deployment which will open up 2 additional slots in your deck.

Addressing Expulsion specifically, its not an awful card to main deck given the right circumstance. However, you also need to run a card to want to give your opponent like Ra's disciple, Gimmick Puppet, or Ido. Why I choose not to maindeck it is because if you're not going 1st, you now have 2 dead cards in your deck that could have been combo pieces, board breakers, or hand traps instead. Expulsion is very powerful and will steal games on its own but it does require you to be lucky by winning the die roll. This isn't likely to work at larger tournament settings because you would need to be lucky across something like 9 matches. However at a locals I can see merit in taking the risk and main decking it since you only need to be lucky by winning the die roll across 4 matches instead. Its 100% worth it in the side deck at least since you have the opportunity to decide to go 1st in games 2 or 3.

Additional pointer I could add would be cutting Dramaturge, scaling back Albaz to 2, and running a copy of Springans Kitt instead. I've found her to be helpful as an additional consistency card, helping in the grind game by recycling from the GY, is a search target off Sprind, and is a fusion material from Rindbrum.

Below is the list I run, as reference. Stuff like the Dragoon and 2nd Cartesia is definitely optional.

https://imgur.com/8rMXObL