Tips for visualization and time management?

As someone who just started playing 10+2 at a chess club and hopes to play tournaments soon, I’ve had to make many adjustments to play close to my online level (1850). Although in a few games I’ve improved a lot, I’m really struggling in terms of time management as my clock almost always leaves me at a significant disadvantage (easily 5 minutes less every game). Additionally, I’ll regularly go into situations where there are calculations to do and just avoid them as I don’t feel I have time to figure it out or I’ll just get super stressed mid calculation and completely miss extremely basic stuff. I think my issue is my lack of confidence in my visualization and poor time management skills. How do I train these more specifically outside of just playing more and grinding tactics?