With OVH you pay a setup fee, and after that about 4 Euro a month for a VPS with 17 IP’s. And if you can get IP’s for $1 a month you can use them with more accounts on 1 proxy.
You blame putting 2 accounts on 1 IP for the loss of Twitter accounts. But only that cannot be the reason. I use 3 accounts on 1 IP without problems.
I do know that with Twitter you have to be carful and not use the same actions on accounts on the same time.
For example; You start with 1000 accounts. Bought. They were made by someone in Russia. All in a row on mail.ru emails. They were offline for 3 months. You quickly verify 500 of them on 500 proxies, 1 acc on 1 proxy. The next day you put 500 extra accounts on these 500 proxies. You can be sure that you will lose most accounts in a day. They connect accounts, all where made in 1 day, they were all verified in 1 day, they all got a second acc on the same IP in a day. Twitter connects accounts, sees them as a group, and will disable all of them.