What is your SOP when planning a transfer on day X, just transfer on the day itself or try to monitor exchange rate just before/after (if so, how long will you wait)?

Yeah that part I'm clear (OP is very well written), but day to day rates will change right? How often do InstaRem/TW etc. update their rates, and is it ever worth it to wait a few days (or transfer earlier than your planned)?

Is it just me or are TransferWise/InstaRem/BigPay all super much more expensive than SunwayMoney for SGD transfers now?

For 10k amount, the rates I'm seeing now are:-
BP - 3275.20 SGD (fees RM5)
Insta - 3270.22 SGD (fees RM45)
TW - 3271.82 SGD (fees RM56.72)
Sunway - 3281.71 SGD (fees RM-3.99)

Even though I have a RM60 transferwise coupon I'm not sure using it makes sense. Let's say I increase my transaction to 30k (only send 29940 from Sunway Money and TW to make comparison fair in terms of cost)

Sunway receives 9826.80
Instarem receives 9810.65
TW receives 9797.79

Is there something I'm missing here?

If they're not competitive then why are you worried for your account to be closed? Can always request re-open if needed in future (and verification is done online anyway).

Sunway Money didn't allow my e-KYC, so I had to manually verify my identity at their booth in Sunway Pyramid. Was less than a day after that that I got the account working.

Don't think sunway money has a customer-to-customer referrer code. If you check their facebook account last month they had an RM30 promo, the code on signing up is for those sort of code.

Can it even transfer SGD? For me it only shows other SEA currencies, no SGD, no USD, no Euro

It beat wise for me last week as well (for LKR).