Unable to set pool and timeout settings in databases other than the one the app uses per environment

I’m running rails 7.0, and having a bit of trouble configuring the pool and timeout for one of the databases the application needs.

My database.yml file looks like this:

development:
  (my dev env settings here settings here)

production:
  adapter: <%= ENV["PROD_DB_ADAPTER"] %>
  host: <%= ENV["PROD_DB_HOST"] %>
  database: <%= ENV["PROD_DB_DB"] %>
  username: <%= ENV["PROD_DB_USERNAME"] %>
  password: <%= ENV["PROD_DB_PASSWORD"] %>
  port: <%= ENV["PROD_DB_PORT"] %>
  pool: 5
  timeout: 5000

my_other_database:
  adapter: <%= ENV["MY_ADAPTER"] %>
  host: <%= ENV["MY_HOST"] %>
  database: <%= ENV["MY_DB"] %>
  username: <%= ENV["MY_USERNAME"] %>
  password: <%= ENV["MY_PASSWORD"] %>
  port: <%= ENV["MY_PORT"] %>
  pool: 20
  timeout: 10000

I have confirmed the ENV variables are passing the right values

One of my rails models needs to connect to “my_other_database”, which is different from the database that the app uses, and I have that setup as follows:

class MyModel < ActiveRecord::Base
    establish_connection(:my_other_database)
end

According to what I see in the documentation, that is the way to set it:

https://apidock.com/rails/v7.0.0/ActiveRecord/ConnectionHandling/establish_connection

But when I run my application and try to use that model to pull data, I get the following error:

No connection pool for ‘MyModel’ found.

If I change my model to look like this (according to that same documentation):

class MyModel < ActiveRecord::Base
    establish_connection(
      adapter: 'adapter here',
      host: 'host here,
      database: 'database name here',
      username: 'username here',
      password: 'password here',
      port: 'port here',
      pool: 20, (notice these two are not part of the documentation, but I just don't know how else to try them)
      timeout: 1000 (same as the other above)
    )
end

Setting the model that way (almost always) works… with high traffic, it seems to timeout sometimes, with this error:

could not obtain a connection from the pool within 5.000 seconds (waited 5.007 seconds); all pooled connections were in use

Notice the “within 5.000 seconds” part. It seems it has ignored my “timeout: 10000”, and fall back to the default

So I am a bit confused. Why would establish_connection(:my_other_database) doesn’t just work as advertised in the docs?

And why if I do it the other way, it just ignores pool and timeout, and falls back to the defaults?

Is there a way I could force pool and timeout to what I need them to be in that establish_connection block some other way?

Please help!