Is it true that if you do not have earnings or you don't get hired by a client/clients after one month of being an active member, your account will be switched to private and you would need to upgrade to a member plan? If that is true, can you suggest a way so that I can still continue submitting proposals? Thank you.
Yes and no. It's true that if you don't earn for a month, your profile is set to private unless you're on the plus plan. However, even if your profile is set to private, you can submit proposals. The only difference is that you won't show up in search results, so you won't get invites.
You can also request to have it set back to public. There's a button to automatically submit a ticket to revert your profile to public on this page. You don't have to be on the plus plan for this to work.