Thank you very much!
So I did some diggings and found out about how to properly used them.
I thought explaining it here for other people since I didn't see any info about it anywhere else that is easily found.
You open it from the menu. Tools - data - encounter database.
OT version is what pokemon game you play. I selected "sword" to filter out all the non relevant results from other games.
I didn't tried selecting pokemons from other games but I am sure more advanced users here did and can help with that.
You then have all the possible encounters for that pokemon on the screen. I chose Blipbug for that case. You have wild encounter. Static Encounter and egg.
You see even the range of levels the pokemon is available for each encounter.
I chose wild encounter since this was my goal.
Last part is just setting up the parameters. I will not go about this since there are other guides for it already.
What I will say however, I see a lot of posts about legality everywhere. It made me think I cannot make the pokemon to work if its not fully legal. But it seems that is not the case.
I inserted multiple non legal pokemons and they worked just fine. I played with them for a few hours, leveled them up, evolved them and it just works.
Legality is important for multiplayer and being connected to the internet. I had one time which a pokemon didn't worked at all. It had black pokeball symbol inside the in game box.
I just removed it and inserted a new one and it was fixed. I assume I messed up some of the settings that resulted in this problem. I maybe even could just do some editing on that pokemon and it will also work without a removal and replace.
Well I hope that other people like me that have no idea about all this advanced, multiplayer and legality stuff and just want to have a better single player experience.
I first found out about save file editors in Final Fantasy Tactics. It was a great tool and pretty convenient.
The only downside to a save editor as opposed to something like cheat engine that let you encounter the pokemon you want. Is that you won't get the more organic experience of encountering it, fight it, and then capture it. I think this experience is quite fun and can be even more notable when you want a legendary pokemon or something like that.
Luckily enough. In pokemon sword and shield we have easier access to legendary pokmons. So you can do a work around be adding a level 70 pokemon with PKHeX and use it on the Crown Thundra to battle a legendary and then capture it.