Yes, I have here a book published in 1997 which tackles the entire Book of the Revelation, and the verses you ask about are dealt with. I will quote from relevant parts explaining the meaning of chapter 4 verses 5-6, but first I would point out that the author takes verses 4-8 as setting forth four principle things, four descriptions, that all show an aspect of fourfold positions relative to the throne of God in heaven. He is keen to stress that everything in this world and that which is to come depends upon its relation to that awesome throne. (The Revelation of Jesus Christ, p92, John Metcalfe) Please bear that in mind as I now quote the interpretation of the sea of glass, as like crystal:
"Before the tabernacle [on earth] and nearest to it, stood the laver,
which in the later temple is called the sea. Here the priests
washed their hands and feet before performing their divine service,
lest they died. Continually kept clean by the washing of water of the
word, the washing of the saints is seen to be through the
condescension of Christ, when he laid aside his garments, girded
himself with a towel, and, taking a basin, washed the disciples' feet
from the earthly dirt of this world.
Here the four and twenty elders are seen as raised from the dead and
seated in glory. There is no need of washing now. The laver, or sea,
is solidified, just as they are for ever purified to perfection. The
laver is now a sea of glass like unto crystal, a witness forever that
its properties have more than fulfilled their function, standing in
eternal witness to the effectual washing of the saints or ever they
were raised from the dead to ascend in glory, to be seated in view of
this everlasting testimony to the grace of God that bringeth
salvation." (Ibid. pp 100-101 - emphases mine)
The interpretation calls upon the Old Testament basin, called the laver, or the Sea (Exodus 40:30-32 & 2 Kings 16:17), to show the need for the priests of God to wash in water in a particular way, otherwise they would die. In the earthly temple, the Sea was a great bronze basin placed atop four bronze oxen. But, having been properly washed, they could enter fully into that divine service of God. The New Testament speaks of all believers in Christ being "priests and kings unto God" - Rev. 1:6 & 5:10 & 20:6. All believers in Christ have been properly washed by him, and then there is the illustration of Christ washing the feet of the disciples (John 13:14 but note vss 8-10).
This leaves us with the matter of how we will relate to the sea of glass before God's throne of glory. Only those who have been cleansed - washed - by Christ will ever see that throne and that solid crystal 'sea' of glass. But if we try to get clean any other way than by Christ cleansing us, we won't be there.