I've tried to upgrade Kathril precon on a budget,I have no experience in deckbuilding and I would really appreciate some suggestions :)
https://deckbox.org/sets/2732655

Have you listened to the Command Zone podcast before? They do a series for each Commander release focused on this very thing -- a budget (around $25) upgrade by changing about 10% of the deck (though they often end up mentioning more than 10 cards to add or remove if you'd like to change it more). Great series. It also analyzes which commander has more synergy and support right out-of-the-box (spoiler: it's not always the face card), and helps focus the deck a bit more on that strategy.

Here's a link to the Kathril deck: https://youtu.be/9Y5Wms1gMaA Although, if you don't like watching videos or just don't want to watch the whole thing, they put a link to their upgraded decklist in the video's description.

Hey,thanks for your reply.
I've watched that and a few other videos and written articles about upgrading the precon and that is where I found the most of my upgrade ideas. I tried to combine upgrade suggestions from all those sources and add some cards which were not mentioned,but I really liked those. I do not have much experience in edh deckbuilding so I am not sure if my ratios(of everything) are good and if some of the cards I have added are simply not that good.