Judging from the support article, it's not possible to merge accounts. If you use Galaxy you could possibly add your installed games manually on your other account, but that would only let you launch them, not download/update them.

See also this support article about adding games manually to Galaxy.

You can't merge accounts.

https://support.gog.com/hc/en-us/articles/360018737498-Can-I-merge-GOG-accounts-?product=gog

can i move the games over to my other account?

Unfortunately not. It's basically the price you pay for DRM free; GoG can't guarantee that you own both accounts and as (with DRM free) removing your ability to download an installer doesn't remove your ability to play a game, they won't do it.

If you created your second account recently and purchased a game through it recently, you could refund and repurchase through your main account. But - if you're out of the returns window, you probably can't.

It should be possible, and it's stupid that it isn't possible.
I'd suggest writing to Piotr Karwowski himself.

Only if it's manually done and done carefully with deliberation over the validity of the person's identity and ownership of both accounts.

If GOG automated this it'll be a disaster.

You'd like to write a lot of things to that guy recently

100% agreed. Can you imagine the abuse were this automated?

Is it annoying if your games are split across two GoG accounts? Yes.

Is that annoyance a price worth paying for a DRM free store? Also yes.

two accounts both alike digitally

I mean...he is the managing director of this place.
He's the one for all intents and purposes, keeping the engineer's hands tied.

That doesn't make much sense.

First, DRM-free has nothing to do with.
From Steam:

"Can I Merge Accounts
Steam accounts can not be merged together. Per the Steam Subscriber Agreement, Steam game subscriptions / CD keys are nontransferable and cannot be reset / moved between Steam accounts."

Second, if GOG really wanted to, they have a good number of ways to ensure that with reasonable probability the person owns both accounts. They can check IP addresses, they can check credit card information, they can send verification emails and ask, for instance, person to answer a question sent to one email address by using the other email and so on.

But in the end, connecting that to piracy issues in any store is kind of ridiculous. People have always the option of not using any store and simply downloading warez. Somebody attempting to merge two accounts has at least paid something sometime, so as an anti-piracy method merging accounts would be more than recommendable.

Anyway, to finish my rant here, I don't understand how someone can accidentally have two separate accounts. Those accounts don't create themselves, you need to fill in personal information, click on all kinds of verification messages and so on. And there are ways to prevent double accounts, such as not allowing the use of the same email.
So how is it even theoretically possible to make a mistake and suddenly end up with two accounts?

I don't know OP's story but I did manage to do the same thing on Uplay. Got From Dust on Steam, had to create a Uplay account specifically for that game, beat it, did not use Uplay for 2-3 years after that, forgot that I had ever made a Uplay account, got hacked on Origin which prompted me start using a new email address for gaming accounts, wanted to play some Asscreed, accidentally registered another Uplay account and started buying games for that one. Now I have one account with like twenty Ubisoft games and another one with From Dust.

What I'm saying is that when you have a DRM free environment, you cannot guarantee that access to downloaded files has been removed from the previous owner. When you've got something like Steamworks, you can prevent a previous owner from accessing content, even if it's downloaded (the fact that Steam doesn't allow a change to ownership being neither here nor there) by turning off access to the downloaded game. You can't do that with DRM free installers.

I'm a big fan of DRM free, but I'm also a big fan of making sure that everyone who plays a DRM free game has purchased it from the publisher rather than reselling it on the secondary market. I'm sure that is an unpopular opinion here, as is my opinion that refunds on GoG should only be available for genuine technical problems that cannot be resolved (or that there should be more anti-abuse restrictions on them).

DRM is not really a matter when it comes to moving games from one account to another. In the end they just don't want you to.

If you want to have all your games on one account, then don't create separated ones. The end.