Agree with @titchy, you need to reframe your 27 years as self employed. Not for the purposes of job hunting, but for your own self worth. To run a self employed business for 27 years is no easy feat and you should be proud of that.
It's also worth remembering that people do have time out of working for lots of different reasons and there is nothing wrong with that. You just need to put a positive spin on it for the purposes of finding a new job (if you are going to work in certain industries eg education, nHS, they will need to know the reasons for a beak) eg 'after successfully running my own business for 27 years, I took a career break to study/enjoy the fruits of my labour/care for family/travel etc then covid hit, but now I'm in a position to re-enter the workforce'
You will also need to spend time preparing for interviews. The types of things they will ask you about will include - communication, priortising your work, team working, dealing with conflict.
You can use examples of your self employed time eg dealing with a difficult tenant. You could also point out that being self employed meant that you had entire responsibility and had no manager to refer to, so you are excellent at problem solving.
You also need to read up on current workplace matters eg refer to organisational policies and procedures (even if you don't have site of them, just say you would read the policies and check of you don't understand).
Swot up on diversity, health and safety and safeguarding, as these can be mandatory questions.
Pull together some good examples that you can call upon in interviews.
In terms of job hunting, it may be woth trying some recruitment agencies for temp work. You may have to prove yourself, by taking on some less than ideal jobs, but if you prove yourself, they will give you better jobs. Employers will often take on good temps directly.
Don't forget, employers are also struggling with recruiting good staff. I work in HR and see first hand the difficulties my organisations have in getting good staff, so it is a two way street.