You're making 20M, you spend probably less than 500k between you and 3 juniors.
I've lead rewrites in worse circumstances (larger codebase split in 30 microservices, 15 people across 3 teams, making just 2M per year!) and I don't think you can do it with your current team. In the above examples we downsized the teams to 1 team with 4 people and then rewrote to 2 rightly sized services.
The new team was all new people (introduced gradually), while we shifted out the previous employees to other areas of the business.
The bottom line you have to use with management is you need a more senior team. Hiring seniors is pretty hard nowadays and it doesn't sound like you can offer much of an environment.
Get a good agency for 1M / year and let them work with your team to understand the ins and out and then replace them.
I've lead rewrites in worse circumstances (larger codebase split in 30 microservices, 15 people across 3 teams, making just 2M per year!) and I don't think you can do it with your current team. In the above examples we downsized the teams to 1 team with 4 people and then rewrote to 2 rightly sized services.
The new team was all new people (introduced gradually), while we shifted out the previous employees to other areas of the business.
The bottom line you have to use with management is you need a more senior team. Hiring seniors is pretty hard nowadays and it doesn't sound like you can offer much of an environment.
Get a good agency for 1M / year and let them work with your team to understand the ins and out and then replace them.