Hi @Kazuhito,
Yes, that is possible, via various means,
You could possibly create a variable in powerautomate, By using initialize Variable: Var,
Define it as your email value, and plug that into the email address location,
Alternatively, You could also have a spreadsheet where you update the email address, and have powerautomate pick up that value from the spreadsheet, e.g. using a list rows action, and then extract the dynamic content of the email, and paste it into the email address location. The same process can be done if the mail is defined in a sharepoint list as well.
You can use any of the options I mentioned to achieve your request, the advantage of the excel option is, You may just have to update your spreadsheet outside the flow environment, and the flow would be updated, If you use the variable approach, you may have to go into the flow on occasions you need to redefine the mail, and change it there.
Kindly feel free to like my post and mark it as a solution to aid others in the community.