It's a decently good example, and it even shows that BIG players will frequently have to go through a kind of process in which it takes time to become profitable, even when MSTR/Saylor started out as profitable with his first purchases for himself and for his company to be in the $10k price territory.. but they continued to buy, and even bought really large amounts in the $50k arena.. which surely brought their costs per BTC up a lot.
In regards to lessening or stopping your buys when the BTC price is above $30k, I am not sure if that specific idea is good - even though surely there can be some value in terms of buying more BTC on price dips and perhaps buying less BTC when it surges up in price a lot.. but then there becomes a question regarding whether the current price (or above $30k should be considered a surge, or what might be a fair characterization of supra $30k prices these days).
Buying on dips is good and perhaps you can try to strategize in order to not be buying on the extreme price rises and then just waiting for further dips; however, if the price goes above certain price points, and then does not end up dipping sufficiently to satisfy your later "buys on dips", then what are you going to do? especially if you might have cash regularly coming in, then where are going to put that extra cash? just let it build up? or maybe you end up panic buying at much higher prices? Maybe you allow your cash reserves to build up to a certain point and then rethink the matter? that would not be a bad approach.
In the end, you are the person who is in the best position to figure out how to deal with your own BTC portfolio and to figure out the extent to which you have enough BTC.. and whether it matters if some of your BTC purchases continue to be higher than previous buys.
Part of the ongoing measure of bitcoin's value has to do with the bottom ongoingly moving up with the passage of time, and personally I consider the 200-week moving average to be a very good bottom indicator, even though we did have some unprecedented times in which it was breached for considerable amounts of time in the last year-ish.
https://www.lookintobitcoin.com/charts/200-week-moving-average-heatmap/
So in terms of BTC value, $30k now is not the same as $30k one year ago, and currently we are barely above the 200-week moving average, which is now at $26,665. For sure, there are no guarantees that the 200-week moving average will continue to serve a decently good bottom indicator, so you have to come to your own determinations regarding whether you believe that you need to slow down your DCA and/or your BTC accumulation based on current prices, with perhaps overly greedy thoughts that you might be able to buy cheaper.. and surely you might not be able to because bitcoin tends to be a very good buy when it is at below or even within 20-30% of the 200-week moving average.
For example, in May/June 2022 when a lot of the disasters of our then over-leveraged (and gambling scamming twats) were being revealed, the 200-week moving average was ONLY in the $21k to $22k price arena, so if you thought that buying below $30k was a good value, in May/June 2022, $30k would have had been around 40% above the then 200-week moving average, and currently $30k is ONLY around 12.5% above the 200-week moving average.
So you are in dangerous (and maybe even out of touch irrational territories?) if you are wedding yourself (and your ideas) to strict thinkings of absolute BTC price thresholds (like $30k) rather than attempting to consider your price thresholds in terms of a somewhat more solid bottom indicator, which I would consider the 200-week moving average to be decently good (even though moving target) of a solid bottom (good value) indicator.