I’ve dabbled in Affinity designer and photo. I use Adobe Illustrator now for work but am slowly learning designer as it probably will replace AI in the future. I won’t pay Adobes software ransom demands.
Designer has been going since 2014 so it does have growing pains trying to get on par with Illustrator. ( I won’t say it is riddled with bugs, just not as feature rich as AI )
Photo on the other hand is a viable PS replacement. (more money in creating a PS app than a vector app)
That said, it should work fine for most if not all your needs.
Really though, there is no other alternative AI when doing large files/maps.
If you are not in a hurry, check the app store on major holidays as these do go on sale. I think I got mine on the July 4th or Black Friday sale.
Hope this helps.
Robert