What factors are causing the decline in Bitcoin today
If you want to find what factors caused this drop today, you can find it on social media, newspaper, everywhere. Because news will satisfy you and make you feel those factors are actual causal contributors of the drop.
But if you don't read news, don't care about news, you will see Bitcoin actually needs a correction. It is what it should be, a correction and this correction is still smaller than many past corrections of Bitcoin.
and what could be a strategic entry point if it falls below $40,000? Has anyone got any technical analysis?
Go with fundamental rather than technical.