My fear is that this will come across as preachy, that’s not my intent at all. I enjoy philosophical discussions but I know this isn’t really the right venue. So for brevity sake, you’ve faced some pretty serious health scares in the past and I know that can really shape future thoughts. (I wasn’t always this cavalier about ‘what ifs’ myself )
But as I’m reading the rest of your reply, what I’m seeing is; Whatever worry you had prior to the surgeries, whatever ‘what if’ you’d told yourself that created the anxiety, it didn’t matter in the end. What was going to happen, happened. You went through the events and came out on the other side with a sense of relief for what [didn’t] happen. ☺️ When the worst happens, we deal with it at the time. Worrying about what, when or how (the unknowns) just robs us of so much mental space that could go for positive affirmations!

I had a paradigm shift in my 30s (30+ years ago) and changed my “what ifs” to If Then. I realized I spent the first part of my life worrying for nothing. Now, anytime I get a what-if moment, I quickly change it to If-Then. If something happens, Then I will deal with it head on. It takes time to reprogram ourselves but it’s possible.
I’m not saying it works for everyone. As humans, we’re so good at telling ourselves stories and I don’t know why we tend to go negative. So make the story positive with a happy ending.

If your lymphoma progresses, then the action will be taken to treat it. Yes, there would be stronger chemo, sometimes targeted therapies, which always sounds scary. But it is a means to fighting the invader and winning. I looked at chemo as an ally in my war instead of dreading it. A stem cell transplant, from my experience, was not a walk on the beach but it was an incredible journey and one I’d do again if I needed to.
For your sake, I do hope you won’t have to face this in the future but if you must, just know it’s all doable, survivable and can have a happy ending. ☺️