OP If you where on a budget you could change just the disc which IMO would make more difference than the ram. I say this as I upped the ram in my wife’s 2012 MBP from 4 to 10 (note one 8gb chip can be cheaper than 2×4 and yiu end up with 10 not 8, it runs fine you don’t really need matched pairs)
You can run a disk speed check by down loading the free BlackMagic speed test programme. I suspect you’ll see a read/wrote speed around 30-40. An SSD will run st 250. FYI I put in a normal hard drive running at 7200rpm vs 5400 as standard which made a big difference and is much cheaper than an SSD (eg 750gb hard drive is £65).
Not sure how “techs” you are, ram is trivial but the drive change requires a bit more care in terms of software transfer, the best is to “clone” the drive by attaching the new one to the computer in a cheap external cradle. Then try booting from the new one while it’s still outside the machine, if all goes well put it inside
@gabe if you’ve the budget buy a new machine and sell your old one, you should get £500 maybe more I think