Protecting against Password Manager getting hacked

I am thinking of using a password manager. I am having trouble to trust these managers. My fear is that a password manager becomes a single point of vulnerability.

Here is an idea to protect passwords.

Say I want to store the password: ykT%mK#5 (just an example). Instead of storing it as is. I would apply the following algo:

1. Reverse letters

2. Add character at 5th position (1 based indexing)

So the stored password becomes: 5#Kmd%Tky (added letter d)

The above is a sample algo. But I think this it is easier to remember algo (It is like your own simple encryption function). One can have different algos for different categories e.g Banks, Email, Github, Office, etc

Question: Does this strategy make storing things in Password Manager more secure in case its compromised?