help with deck transformation for BO1 to BO3

Hi guys, I need some help optimizing my main deck for BO3 (ranked, historic) and I would like some advice on what to put in the sideboard. thanks for the help

Deck

4 Crawling Chorus (ONE) 8

5 Forest (FIN) 308

4 Skrelv, Defector Mite (ONE) 33

4 Skrelv's Hive (ONE) 34

2 Mirrex (ONE) 254

4 Venerated Rotpriest (ONE) 192

5 Plains (FIN) 294

4 Slaughter Singer (ONE) 216

2 Elspeth, Storm Slayer (TDM) 11

4 Synchronized Charge (TDM) 162

2 Surrak, Elusive Hunter (TDM) 161

4 Jawbone Duelist (ONE) 18

2 Bloated Contaminator (ONE) 159

2 Radiant Grove (DMU) 253

4 Razorverge Thicket (ONE) 257

2 Snakeskin Veil (STA) 57

1 Lush Portico (MKM) 263

2 Temple of Plenty (FDN) 703

1 Blossoming Sands (TDM) 251

1 Requisition Raid (OTJ) 26

1 Not on My Watch (MKM) 28