Here is what the latest logs say:
07:29] [main/FATAL]: Failed to start the minecraft server
com.google.gson.JsonParseException: com.google.gson.stream.MalformedJsonException: Use JsonReader.setLenient(true) to accept malformed JSON at line 1 column 1 path $
at net.minecraft.server.v1_16_R3.ChatDeserializer.a(SourceFile:495) ~[server.jar:git-Paper-"ae892dc"]
at net.minecraft.server.v1_16_R3.ChatDeserializer.a(SourceFile:545) ~[server.jar:git-Paper-"ae892dc"]
at net.minecraft.server.v1_16_R3.ChatDeserializer.a(SourceFile:541) ~[server.jar:git-Paper-"ae892dc"]
at net.minecraft.server.v1_16_R3.ChatDeserializer.a(SourceFile:549) ~[server.jar:git-Paper-"ae892dc"]
at net.minecraft.server.v1_16_R3.GeneratorSettings.a(GeneratorSettings.java:236) ~[server.jar:git-Paper-"ae892dc"]
at net.minecraft.server.v1_16_R3.DedicatedServerProperties.<init>(DedicatedServerProperties.java:127) ~[server.jar:git-Paper-"ae892dc"]
at net.minecraft.server.v1_16_R3.DedicatedServerProperties.load(DedicatedServerProperties.java:132) ~[server.jar:git-Paper-"ae892dc"]
at net.minecraft.server.v1_16_R3.DedicatedServerSettings.<init>(DedicatedServerSettings.java:20) ~[server.jar:git-Paper-"ae892dc"]
at net.minecraft.server.v1_16_R3.Main.main(Main.java:104) ~[server.jar:git-Paper-"ae892dc"]
at org.bukkit.craftbukkit.Main.main(Main.java:277) ~[server.jar:git-Paper-"ae892dc"]
Caused by: com.google.gson.stream.MalformedJsonException: Use JsonReader.setLenient(true) to accept malformed JSON at line 1 column 1 path $
at com.google.gson.stream.JsonReader.syntaxError(JsonReader.java:1559) ~[server.jar:git-Paper-"ae892dc"]
at com.google.gson.stream.JsonReader.checkLenient(JsonReader.java:1401) ~[server.jar:git-Paper-"ae892dc"]
at com.google.gson.stream.JsonReader.doPeek(JsonReader.java:593) ~[server.jar:git-Paper-"ae892dc"]
at com.google.gson.stream.JsonReader.peek(JsonReader.java:425) ~[server.jar:git-Paper-"ae892dc"]
at com.google.gson.internal.bind.TypeAdapters$29.read(TypeAdapters.java:716) ~[server.jar:git-Paper-"ae892dc"]
at com.google.gson.internal.bind.TypeAdapters$29.read(TypeAdapters.java:714) ~[server.jar:git-Paper-"ae892dc"]
at com.google.gson.internal.bind.TypeAdapters$35$1.read(TypeAdapters.java:910) ~[server.jar:git-Paper-"ae892dc"]
at net.minecraft.server.v1_16_R3.ChatDeserializer.a(SourceFile:493) ~[server.jar:git-Paper-"ae892dc"]
... 9 more