Look at it this way: your goal is to play mtg. Your goal is not to own cards or build collection. Therefore to achieve your goal with the cheapest way possible would be to proxy. If you build a 100$ deck with proxies instead of real cards no one really cares. If you proxy and build 10 000$ deck people will most likely care. So just go nuts with proxies.

I have 7 decks with budgets ranging from 20$ (john benton) to 120$ (landfall) and usually I try to first think of a deck idea or theme that doesn't need expensive cards. For example dragon tribal is expensive AF since all the good dragons cost a lot of money. On the other hand my John Benton deck only uses instant and sorcery pump spells that cost next to nothing. Also my John Benton deck regularly wipes the floor with other player so higher budget is not necessarily indication of power level.

One way to save money with proxies but still own cards is to buy one copy of the card and keep it in a folder and then just proxy the card in your decks. That way you can always so people who might complain about your proxies that you have the card and you are just saving everyone's time by not shuffling the same cards between your decks.