This is a very good question, @rbrzeg. I did a bit of searching and found this information from trusted health sources.

From Cleveland Clinic.
- When Should You Get Vaccinated if You’ve Had COVID-19? https://health.clevelandclinic.org/when-should-you-get-vaccinated-if-youve-had-covid-19/
“The time frame that we recommend for being vaccinated after having a COVID-19 infection is as soon as you’re out of quarantine,” says Dr. Englund.

There is one caveat, however.

If you’ve received monoclonal antibodies, you must wait 90 days after recovering from COVID-19 to receive the vaccine. According to the Food and Drug Administration (FDA), monoclonal antibodies are proteins made in a laboratory that mimic your body’s immune response.
“If you’ve had that monoclonal antibody, it is going to keep you from being able to develop a nice, robust response to the vaccine. So that’s why we have to wait for 90 days until that monoclonal antibody has gotten out of your system.”

From Mayo Clinic
- Should I get a COVID-19 vaccine if I’ve already had COVID-19? https://www.mayoclinic.org/coronavirus-covid-19/vaccine-if-already-had-covid
Mayo Clinic experts also advise "If you were treated for COVID-19 with monoclonal antibodies or convalescent plasma, wait 90 days before getting a COVID-19 vaccine."

From the CDC
- Can I get vaccinated against COVID-19 while I am currently sick with COVID-19? https://www.cdc.gov/coronavirus/2019-ncov/vaccines/faq.html
"No. People with COVID-19 who have symptoms should wait to be vaccinated until they have recovered from their illness and have met the criteria for discontinuing isolation; those without symptoms should also wait until they meet the criteria before getting vaccinated. This guidance also applies to people who get COVID-19 before getting their second dose of vaccine.

People who have had a known COVID-19 exposure should not seek vaccination until their quarantine period has ended to avoid potentially exposing healthcare personnel and others during the vaccination visit. This recommendation also applies to people with a known COVID-19 exposure who have received their first dose of an mRNA vaccine but not their second."

@rbrzeg, since you were released from hospital 21 days ago, you are no longer considered to be in quarantine and have recovered from the infection. Right? Did you receive monoclonal antibody treatment? What long haul symptoms are you still dealing with?