What is average base pay for 4-5 years across companies like Uber,Atlassian,Amazon,Microsoft,Google?

You should be getting close to 50L easy.

Around 75 to 80 in Salesforce

40+

Yes that should be the minimum base. In some cases base might be 40 but these are all listed to stocks aren't paper money like other companies. Also note the pay here is front heavy (i.e You make more in the first 1-2 years due to joining bonus and more vesting)