I was in a similar position, and moved on to developer roles after spending 10+ years as Test Engineer and Test Manager.

Invested a lot of time in learning
1. Cloud
2. DevOps
3. APIs (Java and Spring boot)

Once I felt comfortable, I started interviewing for positions outside (usually Junior Dev roles). I landed on a contract to hire as a Backend engineer and slowly transitioned to the Senior Engineer role with Elastic as a speciality.

What I found is :
1. Learn as much as you can and identify what you like.
2. Invest more time learning what you like (for me it was Java development)
3. Start thinking and plan for the next 5 year career transition.
4. Lateral move is not easy for QA to other roles except for BA roles.
Cons:
1. Significant set back on your career.
2. Hard to adjust to being a junior dev when you can understand the overall picture much easier than other team members.
3. Climbing up the ladder is exhausting.

Pros:
1. More money.

Advice:
1. Easier to transition to Engineering Lead position if you have management experience.
2. Engineering roles are not as much fun as I would want but better than QA roles.
3. Stick to the same industry if possible.
4. Learn to negotiate with recruiters
5. Fake it till you make it is very risky.
6. Take certifications if possible.

Thank you so much for writing this up. Definitely helps! I have been interested in Cloud and DevOps. I have one certification in Aws and planning to get some more. But practical knowledge is hard to get. I have done a lot of labs etc but nothing like learning on the job with live projects. I gave one interview for a cloud role but could not get through because of lack of experience. Some questions are just built that way. But the 5 year plan seems realistic. I will keep trying. There is just no easy answer.