I also complained in frustration earlier in this thread. The bad performance forced me to google som guides for team instructions. I stripped down my 4-2-3-1 to use only team instructions that I was sure of my team could execute after learning all about the team instructions. Also got some better players. Now I have 10 wins in a row and counting!
It turns out that for your tactics, less is more, depending what instructions your players have skills enough to execute. So if you struggle, I addvise you to try once with your formation almost empty of instructions. Perhaps add only press and counter. See how it goes! It got better results immediately.
Good guides:
(1) GUIDE TO ALL TEAM INSTRUCTIONS : footballmanagergames (reddit.com)
(1) What are some common tactical traps beginners should avoid? : footballmanagergames (reddit.com)
(1) Guide to Team Instructions : footballmanagergames (reddit.com)
[FM21] A Complete Guide to Quick Transitions and Counter Attacking Football - Tactics, Training & Strategies Discussion - Sports Interactive Community (sigames.com)
Basic principles of defending (an unofficial guide for tactical beginners) - Tactics, Training & Strategies Discussion - Sports Interactive Community (sigames.com)