You make no mention of the bare bones information that someone would need to know in order to assist you.

A competitor may have all these 1st mover advantages. The answer depends on if you have a differentiation advantage, more brand reputation strength, and how compelling your ad copy is to targeted personas.

How do you know he has 6000 clients? It also depends on how negligible switching costs may be to switch to your service or product as a substitution for what he has.

A situation analysis is imperative as a first action to determine if what he sells is what the market wants exactly. If not, a slight tweak to your offer, brand, product, and message may be the tiny subtle refinement that makes them choose you over him, or makes them replace him with you.

If you don't have budget for the situation analysis, you won't likely have too many skilled analysts ready to help.

I take it from your post that you are not in the USA, and therefore, would require a consultant to travel abroad to perform the field research in addition to the desk research, so whatever your budget for assistance must also take into consideration that the consultant will need to travel to you and not simply analyze you from the comfort of their armchair.

For a little no cost advice on what you can do in stealth mode for analysis and save a little seed capital see

How to Use a Competitor Dashboard to Destroy Your Competition https://www.cyfe.com/blog/competitor-dashboard/