Thanks for the post. Glad to hear you are going at it. If you are in the midst of the season now you may want to start with one of the building block plans to add a bit of structured intensity to your training in small chunks. Under the plans section, choose cycling then building blocks. From there you can choose the specific type of block. You mentioned threshold but I recommend that you start with MAP or AC/NM especially if you are doing crits as these are both helpful in building FTP and more likely to help with any type of mass start racing. Cheers!
That’s a great plan for ANYONE wanting to up their FTP/MAP. Need to work on VO2 if you can as well for the times when you need to put power to the pedals to stay with the pack or avoid a major issue. AC/NM training there helps (surges…)