Full Stack Developer to repair security flaws | GOlang & Rubby on rails -- 2

Hello, i have an app which is 50% Golang, 15% Ruby, 12.5% typescript, 12% HTML.

It has some security flaws which need fixing. For example:
-Password policy change to not allow easy passwords
-Prtotection against Injection attacks (e.g. HTML injection, XSS, command injection)
-Broken Authentication and session management - Bypass 2FA Authentication
-Access control-related misconfigurations
-Software misconfigurations
-Sensitive data exposure
-HTTP Request Smuggling
-Open Redirect
-Cache poisoning - Header Injection
-Clickjacking

I am looking for someone who knows how to fix security flaws.