Tips for a park the bus tactic

Anyone here experienced in "parking the bus" style of football? For some context, I am with Estoril Praia (Portugal 1st tier atm) just won the league and the cup in my 2 years at the club, we are now in the Champions league group stage with 3 very strong teams in comparison (Spurs with Kane and op regens, Barcelona with all the world's best talent and Monaco with some powerful newgens and wonderkids). The whole of last season I spent on upgrading my classic 442 aswell as creating a more attacking 4231 and a more defensive option. My biggest trouble in FM is defending in general, even though I love defensive football irl taking inspiration from the likes of Sergio Conceição and Mourinho. Anyways my 433 is very negative minded as I needed something for the "big boys" in the UCL, but since I'm not the greatest when it comes to tactic building I decided to ask for opinions here. I've tried some small changes but in general here's what I mostly used in 3 games against very hard opponents: (Away) 1-2 win vs FC Porto in the league (2,69xG vs 1,20xG) (Home) 3-0 win vs Spurs in the UCL (2,67xG vs 2,12xG) (Away) 0-1 loss vs Barcelona in the UCL (2,62xG vs 0,15xG) I'm very impressed with the 2 UCL games as we were defo not the favourites to win but managed to get some solid attacks going aswell as plenty of set pieces against spurs and a game where I nearly thought we could draw against Barcelona with an xG of 0,15 lmao. Long story short, any tips on how I can improve anymore defensively or maybe in attack? Would love to hear suggestions from you guys! :D (I will post some of my key players aswell as the formation itself)