dnd 5e – Less-lethal Wild Magic Surge homebrew

I’m playing a (Wild Magic) Sorcerer in a game of D&D 5e. My DM has house-ruled the Wild Magic rules and I am not privy to the details, but here’s what I’ve pieced together:

  • As usual, a d20 roll occurs anytime you cast a spell of 1st level or higher. The cutoff for triggering a Wild Magic Surge is not 1, but somewhere around 12-14 (i.e., anything below a 12-14 triggers it).
  • Upon using Tides of Chaos, you roll a d20 immediately, as if you had cast a spell. If you score less than the cutoff you then roll on the Wild Magic Surge table, but this does not grant you the return of your Tides of Chaos ability.
  • The DM retains the option to force a roll on the Wild Magic Surge table immediately after you cast any spell, which causes you to regain your Tides of Chaos ability as normal. Otherwise, you regain it on a long rest.
  • An alternative Wild Magic Surge table is used. This table has some area-of-effect-centered-on-caster damage or vulnerability spells added in, and seems to be more deadly than the default. (I’ve killed one friendly NPC outright and one PC indirectly in my last two rolls, + had a handful of other lethal or damaging events happen in our ~6 sessions so far.) I haven’t seen the table, though, so that could be simple bad luck. (And I don’t know what fatality rate is expected for the “normal” table, either — I just get a feeling by skimming through it that it’s lower than ours.)
  • Spells cast due to Wild Magic Surge do not count as spells cast by you (so metamagic like Careful Spell, etc., cannot be invoked).

I think my DM’s major goal with the above is to ensure that wild magic features appear more often and are more unpredictable than the default.

I recently reached the conclusion that my Sorcerer’s Good alignment is not compatible with using the Tides of Chaos ability, because of the high observed risk of collateral damage / bystander deaths. (I ballparked it at about 15-20% each time ToC was used.) However, when I mentioned this to my DM he was concerned, as he said “tides of chaos is a big deal down the line” and he didn’t want me to limit myself. So now I’m thinking that maybe I should suggest revising the house rules to make Wild Magic Surges less lethal, while still serving the goals of keeping them unpredictable and relatively frequent. Unfortunately, I’m a very new player and I have no experience with homebrew anything.

I’ve searched, found a lot of Wild Magic Surge tables, and have no idea how to assess which ones might involve less collateral damage. What strategy can I use for balancing a homebrew Wild Magic Surge table, or judging how balanced someone else’s is? And are there any other places in the above rules that seem like targets for tinkering to reduce the number of deaths per session?

(By the way, please don’t hesitate to comment if this sounds like a problem with the way I’m playing the character, by doing things like using Tides of Chaos in non-combat situations, as well — sadly for me, Googling “wild magic for dummies” produced no relevant results.)