Difficult decisions and I know back issues are never simple. I know a number of people with back problems but all slightly different and treatments are always changing and improving.
Generally I think people cope with medium grade chronic pain as long as they can, perhaps with a support like a back brace eg. But then it depends how debilitating it gets and whether there is any risk from the degeneration. Have you had a recent scan to see if it is any worse or about the same in terms of degeneration.
I would research as much as you can about options 2 or 3. And find out what peoples' experiences after these operations are, and the prognoses etc - before making any decisions. I know with foot surgery for example (depending on the condition) they say surgery is a last resort and can make things better or cause different issues.
As your Doc says injections (are they steroid?) aren't a long term solution.
The Spinal fusion sounds better than the other one to me - not sure why. The Mayo Clinic says this about it, so there could also be other issues later, but that is the same for any condition or surgery I guess
Overview - Spinal fusion - Mayo Clinic
This page has personal stories of people who've had spinal surgery and their decisions - although it is likely to be a bit biased as the page is a medical company, but may have some insights.
Living with a Spinal Fusion - After Back Surgery
This page is some kind of forum for people with lumbar back problems - some negative about surgery but everyone is different and it's weighing up options and pros/cons to the condition you currently have and what pain relief or support helps.
https://healthunlocked.com/painconce...-in-both-legs.
I think all I would say is, if surgery is the next step, then do LOADS of research. Get names - make sure you go to someone who is an expert and has good recommendations. I don't know how it works in the US but in the Uk you can choose who you are referred to, at least for a second opinion, and that means getting a name.
This guy sounds good! And at the bottom it says he doesn't always recommend surgery and sometimes uses more conservative treatment.
Dr. Kevin Gill: One of the World's Top Spine Surgeons: UTSW, Dallas, TX
Another thing to bear in mind is - surgeons like to operate - it is their job and what they get trained for. Have you considered asking to be referred to a pain clinic for pain management where there are a range of things that can help for even the severest pain people have to live with?