Plugin customisation for advertising website

Hello, I'm looking for an experienced developper who already has customised plugins on wordpress and is aware of issue regarding wordpress update. Our website is an advertising platform for aircraft for sale. User submit posts through our website by purchasing a monthly plan. The project has been previously completed by some freelancer in the past but it is no longer working on the latest version of wordpress so it needs to be cleaned up. Functionality that must be fixed: Plugin paid-memberships-pro: - User Light: They are allowed to submit 1 free post the 4 first weeks but they have to accept a prepaid payment on PayPal before submitting their ad. So we can continue their subscription after the 4 weeks. - User Premium: They are allowed to submit 10 posts and they have to pay before submitting the first post. They must be allowed to submit 9 others posts until they are asked to pay again. - Current user registered on our website are allowed to submit posts for free and they should be asked to purchase a plan such as Light or Premium before submitting new post. Plugin PTB Submission: - When a user is entering a new post the keyboard key ''ENTER" is not detected. Which mean we have to edit manually each post and to add <br>. - Field price: user should be able to enter number only - Field aircraft name: it must be displayed automatically in capital letter on the website I'll give more details in private if needed so do not hesitate to contact me if you feel confident about this project. Hopefully we can build a long term relationship.