You don’t need a coach but you could use a local buddy to help you navigate training and racing. Everyone when they start out can use a buddy!!
Almost everyone has self doubt at some point in this type of journey. So go ahead and put those feelings aside but know that they will come back from time to time and you’ll need to chase them away again.
Unpack your expectations and make micro and macro goals. A couple cycles of TR SSB training does not convert a low performing cat 5 into a cat 1 or a club ride stone cold killa. It takes training time and skills to perform well on the road and in races. Give yourself permission to take the time to do the training and to learn the skills. Also don’t believe all the guys on forums saying they went from an FTP of 150 to 350 with one round of training. There absolutely are mutants who do that, or dudes that go from cat 5 to cat 1 in a season. But most people progress much more slowly and over time. Time is years not weeks or months. It’s OK, enjoy the journey and being a healthier person for it.
Training: For a Cat 5 rider, assuming you are relatively new to this, it really dosen’t matter what program you do. Just do one and be consistent and keep doing it. Eddy Merckx famously said “RIDE LOTS”. He’s right. With Trainer Road we can ride smart but you still have to ride lots. I wish we would rename the “base” programs so that folks didn’t see them as something to progress through in 6-12 weeks in order to get to the good stuff, but rather as the long term foundational training they really provide. There would be nothing wrong with beginning riders taking a long period of SST (base) training and doing SSB2 or 3 over and over for several cycles. With some VO2 and some long outdoor rides mixed in.
Racing is about skills in addition to power. My FTP has not changed in years but my race results improve (Cat 3, I stink) by getting better at actually racing. Be it TT pacing, criterium, RRs. Skills matter.
But… If you don’t have enough power to hang with a Cat 5 field don’t waste your time racing just yet. Find some folks to help you with basic skills. How to draft, how to corner.
Once you are ready to race, make your first goal just to finish in the pack. You don’t ever have to pull, breakaways aren’t your thing yet. First learn to finish in the pack then go from there. You don’t need a coach so much as a friend who has already gone through this stage to help you out. It is not hard but it’s not obvious either.
FWIW, I taught my wife to race by going through exactly the progression described. We did rides together then group rides so she could learn basic road skills. We introduced training to a program and spent a couple years at it. When she started racing we taught basic tactics. Mostly what not to do but that is a different post. A few years of effort and focus culminated with a Cat 4 state championship in criterium. Not a huge deal but a nice personal accomplishment for a hobbiest level rider.
An aside, her race bike was an aluminum frame with box rim wheels. You don’t need equipment at the lower levels. Actually at any amateur level. It’s all about the legs and the skills. Folks get hung up on gear because it’s fun to ride nice stuff. But at lower levels it is not at all needed and can become a distraction.
Stick with it and in a year or two you’ll be a Cat 4 and old hat giving advice to the next guy going through the first steps.