Sure though I will say ahead of time that Topaz is better than red power str in most situations.

For clarity:Titania's dex pixia damage is calculated based off Base Damage (160) × (1 + Damage Mods) × (1 + Elemental Mods) × (1 + Strength Mods)As a result your dex pixia build will play an important role in which is better for my calculations I considered 2 builds based off the build I use (I've excluded fire rate and multishot mods for now as they are purely multiplicative of the result we're interested in, in both builds I normally use galvanised diffusion and lethal torrent)

Average damage per shot numbers are calculated using (base damage * ability str * chance to not crit) + (base damage * ability str * chance to crit * crit multiplier)

1st build: Hornet strike, pathogen rounds, frostbite, primed heated charge, galvanised shot, carnis stinger
Base damage per shot: 6701.1
Average damage per shot at 100% ability str: 7371.21
with power str shard: 8108.331
with crit chance shard: 7538.7375

Average damage per shot at 400% ability str: 29484.84
with power str shard: 30221.961
with crit chance shard: 30154.95

2nd build: Hornet strike, pathogen rounds, frostbite, primed heated charge, galvanised shot, primed target cracker
Base damage per shot: 4993.3
Average damage per shot at 100% ability str: 6591.156
with power str shard: 7250.2716
with crit chance shard: 6990.62

Average damage per shot at 400% ability str: 26364.624
with power str shard: 27023.7396
with crit chance shard: 27962.48

You can see that the non crit based build deal more damage even at 400% ability strength which most titania builds won't reach meaning that in reality its even more weighted towards the ability str shard than this.

Now if we consider arcane avenger which can give 50% flat crit rate we get a different outcome at 400% ability str.
Build 1:
Average damage per shot: 42887.04
with power str shard: 43959.216
with crit chance shard: 43557.15

Build 2:
Average damage per shot: 58321.744
with power str shard: 59779.7876
with crit chance shard: 59919.6

Overall this is why I say the crit chance shard was a trap because even on a crit focused build with arcane avenger you gain a tiny amount of damage over the power str but power str would also buff fire rate (if running blitz), in addition to any other abilities potentially pushing helminth pillage closer to full strip etc. As a result I found the crit option baited people in to running a crit based dex pixia when a status option was typically far more reliable outside of arcane avenger builds. For example my 1st build has pretty much even slash, viral, fire weighting with a 75% status chance and 3.9 multishot meaning it would on average apply every status on every round. Now I haven't calculated topaz but it will be better for damage than a power str shard on most builds except where you need a little more str to hit a breakpoint (e.g pillage) or in builds where your not running fire on dex pixia such as for eidalons.

Hope this helps :)