How to get back into riding after a mid season break?

I was training for 15-10 hours per week for the last couple of weeks as I was doing outdoor workouts, and extending each ride by doing zone 2. I completed my A event (600km in 7 days), and then took a week off the bike.

After getting back on the bike, I noticed that my heart rate is 2-4bpm higher than what it used to be, and my legs are very sore. I did a 3-hour hilly endurance ride, and it was really hard on my legs. I was surprised that my heart rate was only slightly higher, but my legs were so sore that it affected me throughout the day. For context, I am 19 years old and I handle high volume quite well (even though I follow low volume plans, I add in a lot of z2-z3).

My goal is to peak again this late November even though I am not training for any event. My plan is to take 3 weeks off from structured training before I jump back in. The first week is completely off the bike (which I completed), followed by two weeks of unstructured riding. I would like to know how do I get back to where I was before after a week off? My FTP was 311w at 67-70kgs. After the break, my zone 2 feels like zone 2 if I go by RPE, but I definitely lost some of my top end fitness.

Oh what it is to be 19, personally I would but your next event in plan builder and start straight away and not waste the further two weeks of unstructured training. I’m guessing it will give you a shortened base, shortened build and than onto speciality. If you stick to your original plan you could be missing out on some re-sharpening

I also want a mental break but I also don’t want to lose my fitness at the same time. That’s why I am doing some unstructured training before I jump back in.