It’s ok to learn during your working hours
Even if your company is not willing to explicitly allow you to learn during working hours, it’s really ok to do it. You can either public book an hour per day/week on your calendar so you can study the subjects you need for your work or you can add to your estimation the time you need to improve your coding skills. Example: a task takes 3 hours, but you are using a new framework, estimate it as 6 hours, so you can spend 3 hours learning the framework. This will reduce the number of hours spend on code review and fixing bugs anyway 😃
Links
https://junglecoder.com/blog/learning-without-burnout https://software-technique.com/