The secret is, "no solenoid click"... and it's is usually a power loss or ground loss at solenoid. the solenoid is "on" or "close to" starter (ie engine heat, loose dirty connection or mounting)
...also... It could be a compromised (border line) solenoid core, due to heat, dirt, rust, water combination... where is your starter solenoid physically located?
...also... It could be a compromised (border line) solenoid core, due to heat, dirt, rust, water combination... where is your starter solenoid physically located?