Affinity Designer is a great alternative tool for vector to Adobe Illustrator. I used Illustrator for years and made the switch a few years ago and at first, it was hard but eventually, I found I could do everything I was doing with Illustrator with a tool that had a one-off fee and lifetime plan and support. I highly recommend a look at Affinity Designer and even taking the free trial for a 90-day spin.
Before you do make a list of those things you use Illustrator for and set out some goals to achieve these same things using the workflows in Affinity. You'll be surprised that you can tick almost all of the boxes and that it's also not a sacrifice in time for the saving.