"I would like to argue that short volatility is a profitable strategy, IF DONE RIGHT." What a conceded view but I hear it all the time. So you are saying all those professional money managers were idiots and didn't know how to diversify and use leverage!?
I think the only way to do it "right" is do it so small that it doesn't even matter IF blow up happens. It sounds like what OP is doing, so I'm looking forward to following this journal.
no it's to do it with hedge; that's the only way. People still don't seem to understand the concept of everything being dynamic in options. "Dynamic" means it changes. It doesn't stay the same. The 0.2 delta strike that you see today is not going to be guaranteed to stay as 0.2 delta until DTE. It may and may even go down but it may increase and when it increases, it could increase all the way to 1 where the price of the option moves on a 1:1 basis with the underlying's value but that's only on DTE, any time before DTE, there is something called time value which will even push the price of the option to above 1:1 basis with the underlying. And since there is no limit to how much an underlying's price can increase to, there is also no limit to how much your loss on that short option can grow to, no matter how small your position if there is no offsetting long option.
This can be easily illustrated with a price scenario analysis with prices at different levels but since the OP is reluctant to do so, I will illustrate it once and for all:
Since the OP loves meme stocks so much, I will take the most meme stock of them all, GME. And I will take a strangle position on GME with 0.20delta for call and 0.21delta for put on Jan. 20, 2021 with 10 DTE to expire on Jan. 29, 2021, and just to be extremely conservative, I will take the smallest position possible, 1 contract each for both call and put representing 100 shares in each:
On Jan. 20, 2021 price of GME was: $39.12
Call with strike of 58 at 0.20delta : $1.375 (mid-price between bid of 1.26 and ask of 1.49)
Put with strike of 30 at 0.21delta : $1.66 (mid-price between bid of 1.62 and ask of 1.70)
So for 1 contract each, the OP would receive total profit in premium of 1.375 X 100 + 1.66 X 100 = $303.5 yay!!!
On Jan. 27, 2021, just 2 days to DTE, the price of GME rose to: $347.51
Call with the strike of 58 that had 0.20delta now had a 1delta and the price all of sudden has risen to: $291.275 (mid-price of 284.95bid and 297.60) Notice that the intrinsic value of the option is just (347.51 - 58) = $289.51 which is what the option is supposed to be worth but because of the time value still left on the option, the price of the option is higher than what that option is worth.
Put with the strike of 30 that had 0.21delta before now had a 0delta and the price has now dropped to: $0.175 (mid-price of 0.16 and 0.19) With the price so low, one might as well let it expire worthless to reap the full profit of $1.66 X 100 = $166 but according to OP's rules, he would TP when the option is at 50% profit so the profit on this put would be $166/2 = $83.00 assuming perfect execution.
Now let's look at the loss on the short call side: The loss would be (1.375 - 291.275) X 100 = -$28,990 not only completely erasing the entire net liquidation capital of $10,037.50 plus the $83 profit from the short put but would also result into a margin call for $(28990-10037.50 -83) = 18,869.5 IF TD did not liquidate the position before. And notice during the whole time of the position being open, there was no way OP would've had any chance to TP at 50% profit. It was immediate loss right from the beginning.
Just for the smallest position of just 1 contract for 100 shares, a huge move like this that actually happened would have not only completely erased all of the trading capital in the account but also would require the OP to put in additional $18,869.50 to pay back the broker's margin loan, cutting into OP's saving of $700K. After this loss, the OP's savings would have been $700K - 18,869.50= $681, 130.5.
And this is just with the smallest contract size of just 1 contract representing 100 shares. According to OP's strategy, he is supposed to be 80% invested with position size of 10% of the net liquidation capital so that's approx. $1000 invested and that would've resulted into $500 invested into each side so that would be presumably 5 contracts for both call and put? Then in this case, the loss would've been 5 times at -$28,990 X 5 = -$144,950 offset by the net liquidation capital of $10,037.50 and the 5 times of the profit from the short put $83 X 5 = $134,497.5 for margin call, a reduction of his 20% of his $700K savings.
Five times of losses like this with 5 contracts each, his entire savings of $700K will be gone!! If the OP has really demo traded in the paper trading account in TDA, he should've already experienced this loss in the paper trading account. I am surprised that the OP would still think that this strategy can work. I hope this scenario analysis exercise can make him realize the potentially huge risk that his strategy could be subject to if he didn't notice this in his demo trading before.