I have built a server at home for working, but in the end I just use it as an ssh server, to reverse RDP to work

Option 1: your office has a VPN, ask for access

Option 2: get a cheap 2nd hand server * in UK there are cheap HP ML310, 50£ * Open your home router port * Setup a dynamic DNS

* Setup a VPN or SSH * From the office connect to your VPN/SSH * From home RDP/x2go/SSH to the office computer

Option 3: rent a 2.50£ a month VPS, with a static IP. Setup as above...