Backup what you need, run the recovery options and do a ‘fresh’ Win 10 install, put everything back on, then pop an SSD in.
Buy a hard drive enclosure. Use free minitools partition wizard, and copy the lot over. Swap drives, once happy, use the old drive as a removeable one.
Depending upon space, try and get an SSD of the size you need. Bear in mind Amazon black friday for some deals.
I got a 1TB SSD for £150 two years ago. That went in a fast laptop that has room for 2 drives. Picked up a 500gb drive also by shopping round.
We’ve got SSD’s in 3 laptops and 2 desktops.
My lads gaming PC needs a fresh install every 12 months, as the graphics drivers stop installing properly.