- Don't care what tech stack you've used
I would argue that most companies aren't too concerned about your tech-stack. You're applying to businesses with dev's who like you appreciate development skills are transferable to other stacks and languages.
HOWEVER, if you are one of 10 applicants, of which 2 just happen to have experience in their tech-stack, then they will get preference over you. This is a logical route for them to go down.
- Have a large enough tech team to tolerate a greater ramp-up time for new hires
If this was the case, they'd be looking for 'juniors'. If you're applying for anything other than that, assume that they don't have the capability to tolerate a slow learning curve.
- Worked on-and-off. I never had another job lined up when I left/laid off from the old one.
If I see a CV with noticeable gaps in employment, I will put it to the bottom of the pile. I suggest you fill in those gaps with something.. personal projects.. volunteering.. you must have been doing something other than looking for your next job?
- Years in the field mean less to them because they can just hire and place someone where it's appropriate
Again I think the majority of businesses don't care too much about years, as such. Context matters. Again, if you're one 10 applicants, and the other 9 have 5 more years than you, then they'll preference them.
Can I suggest you reconsider your approach to applying? 1000 applications in 3 years are almost 1 a day. That's crazy. Your CV must be all over the place, and that isn't always a good thing (for example, if you've adjusted it over time, it may look like you were lying before).
Have you considered sending a portfolio with your applications?