Just to be clear, do you believe that Paul is calling holy days that the almighty eternal God created, such as the day of atonement, "weak and beggarly elements"?
4:11 I am afraid of you, lest I have bestowed upon you labour in vain.
After hearing the gospel preached, Paul is telling them that he is concerned that they understand nothing about Jesus. They cling to the old way of life, the shadows as opposed to the true light.
The word elements comes from root words meaning a cooling as in end of summer, or a chill.
I looked at the verses from a couple of different bibles. The Amplified shows it as :
8 But at that previous time, when you had not come to be acquainted with and understand and know the true God, you [Gentiles] were in bondage to gods who by their very nature could not be gods at all [gods that really did not exist].
9 Now, however, that you have come to be acquainted with and understand and know [the true] God, or rather to be understood and known by God, how can you turn back again to the weak and beggarly and worthless elementary things [[c]of all religions before Christ came], whose slaves you once more want to become?
10 You observe [particular] days and months and seasons and years!
11 I am alarmed [about you], lest I have labored among and over you to no purpose and in vain.
Hopefully the Amplified is in error about Paul meaning ALL religions before Christ, as that would also include Judaism or at least the religions that were given to us by YHWH.
I think and hope that Paul is merely talking about the pagan/heathen practices and feasts.