Security of Vanity Addresses

Question

I found a vanity address with this verified tool: https://github.com/JeanLucPons/VanitySearch

And now I hold my private key, with BTC I am used to only the recovery seed and I don't know what position I am currently in.

Can I get the seed somehow or does the private key replace it?

The primary thing I'm concerned about is I want to receive all funds in the store at my own address and I want it to be as secure as the address I get in any other wallet.

Thank you very much for your time.

EDIT:

I'm doing research, but this topic seems very complex to me and I'm afraid of getting something wrong and putting myself at unnecessary risk, but what I've understood so far: a private key is +/- the same as a seed except that the seed "controls" the entire wallet, while the private key only controls a specific address, so I should have the funds safe even now and no further steps are needed.

I imported the private key into Electrum and encrypted the file.

Answer 1

Do not use vanity addresses from random bitcoin tools/libraries for anything serious.

Generating random private keys is difficult and sometimes old tools are vulnerable.

Answer 2

Can I get the seed somehow [...]

No.

[...] or does the private key replace it?

Not exactly, they are obviously different things. However you need to keep a secure backup of the private-key in the same way you would the seed or seed-phrase.

I imported the private key

Remember that this key will not be restored by restoring your wallet from a seed-phrase (AKA recovery-phrase or backup-phrase). You will have to import it again. There is a risk you will forget or not take adequately comprehensive backups and lose money.

I want it to be as secure as the address I get in any other wallet.

You'd arguably have to inspect the vanity generator source code carefully and only run it offline on a machine that has never been connected to a network and which never will be (unless associated non-volatile storage is all carefully wiped - including unallocated space and taking into account wear-levelling where relevant.)