Quick sketch of I-FGC30452 haplogroup (below I-Y4882)

Y3548 (S17250)>Y4882>Y16473>FT66517>FGC30452:

The I-Y4882 haplogroup prevails in Poland, Slovakia, Czech Republic, Germany and Hungary. I-Y4882 has two main branches: the large I-Z16969 branch and the small I-Y16473 branch. I-Y16473 can be found in Poland and eastern Slovakia.

According to FTDNA's haplotree, I-FGC30452 contains two subbranches: I-BY30329 and I-BY212399:

https://discover.familytreedna.com/y-dna/I-FGC30452/tree

YFull shows three branches below I-FGC30452, and two I-FGC30452* samples

https://www.yfull.com/live/tree/I-FGC30452/

YFull doesn't show the I-BY212399 branch, probably because YFull considers BY212399 to be unreliable. But the I-BY212399 branch is the parent of YFull's I-Y83761 branch, YFull's I-Y419720 branch and YFull sample YF106053 (this is a Big Y sample from FTDNA).

See the combined tree below. Note that the I-FT92965 branch contains a FTDNA sample from Slovakia, and three scientific samples that are shown on the YFull tree: GMP3823, GMP3822, GMP5240 (at least one of these samples is from Poland).

-- FGC30452  -------------------------------------------------------------- YF118814 (Nebula)

                         |

                         |-- BY212399 -------------------------------------------

                         |                          |                                

                         |                          |-- ZS9483/Y910 ------------------  Slovakia (FTDNA)

                         |                          |                             |

                         |                          |                             |-- FT92965 -- Slovakia,Poland 

                         |                          |  

                         |                          |-- FT94816 ------------------------- Hungary (FTDNA)

                         |                                                        |

                         |                                                        |-- BY70878 -- Czechia (FTDNA)

                         |

                         |-- BY30329 ------------------------------------------

                                                    |

                                                    |-- FT355816 -----------------------  Poland (FTDNA)

                                                    |                            |

                                                    |                            |-- FTE75608 – Poland (FTDNA)

                                                    |

                                                    |-- FGC30465 ----------------------- Poland (FTDNA)