Yeap, VWRA unfortunately do not carry small caps, its not ideal but it's impact is smaller than you might think. I've posted this before somewhere else so don't mind the copy paste:
Of course, if you believe in small cap value tilt or factor tilting in general, it's very easy to quickly dig back into the rabbit hole that we just crawled out of, like adding in AVUV/AVDV and just ignore the withholding tax since small caps rarely generate enough dividend to matter, and since they are US listed, the trading cost is way lower, etc.
But my personal recommendation is always, keep it simple, hold VWRA, spend the time on increasing one's income instead.
As for lump-sum vs DCA, it's a much debated topic so I'll just give you my personal opinion:
Time in the market > Timing the market, lump sum should give you a higher return - keyword being should.
While VWRA is relatively stable, with VWRA being basically ~60% US, and lump-sum into a decade long bull market is always scary, can you really withstand your 50k poofing to 30k overnight, and keep holding it for another decade or two?
For me, I have a good 20 year horizon minimum ahead of me, I'm looking forward to a crash to test my resolve, get cheap shares, and I believe in investing in VWRA enough that I haven't really found another place that I would put the majority of my money into (e.g. if for any reason VWRA drops 50% overnight, well, chances are nowhere else is really safe anyway), so personally I will lump-sum that amount in today.
Besides, I think I'll have much bigger regret seeing VWRA go up by 3 dollars when I only deposited only 5k out of 50k and end up panic FOMO lump-sum anyway

thanks for the much valuable insight! I like the idea of a braindead portfolio a lot, coming from someone who thinks buying dividend stocks on Bursa is even too much of a pain, so I think I'll go with your recommendation of VWRA over micro-managing multiple ETFs. Lump-sum investing is a bit scary for me, but I think my investment horizon is definitely very far out, 10-20 years, so short-term volatility shouldn't factor in too much over time.
Just out of curiosity, how often do you top up your ETFs? And are you using IBKR? On IBKR, the LSE commissions seem to encourage less frequent / higher amount top-ups rather than like US exchanges which are $0.35 minimum.